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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Minios-devel] [UNIKRAFT PATCH 1/1] lib/uksglist: A scatter/gather list data structure
A scatter/gather list is a list of vectors, each of which gives the
location and length of one segment in the overall read or write
request. The sg list provides support for the following operations:
uk_sglist_init
uk_sglist_reset
uk_sglist_count
uk_sglist_alloc
uk_sglist_free
uk_sglist_append
uk_sglist_append_sglist
uk_sglist_build
uk_sglist_clone
uk_sglist_length
uk_sglist_split
uk_sglist_join
uk_sglist_slice
Taken and modified from freebsd source commit-id: 4736ccfd9c3
Signed-off-by: Sharan Santhanam <sharan.santhanam@xxxxxxxxx>
NOTE:
Please be aware that this patch uses the update uk_pr_* macros.
Please make sure the patch series "Update libukdebug printing" is reviewed
before this patch.
---
include/uk/arch/types.h | 3 +
lib/Config.uk | 1 +
lib/Makefile.uk | 1 +
lib/uksglist/Config.uk | 8 +
lib/uksglist/Makefile.uk | 7 +
lib/uksglist/exportsyms.uk | 11 +
lib/uksglist/include/uk/sglist.h | 272 ++++++++++++++++++++
lib/uksglist/sglist.c | 533 +++++++++++++++++++++++++++++++++++++++
8 files changed, 836 insertions(+)
create mode 100644 lib/uksglist/Config.uk
create mode 100644 lib/uksglist/Makefile.uk
create mode 100644 lib/uksglist/exportsyms.uk
create mode 100644 lib/uksglist/include/uk/sglist.h
create mode 100644 lib/uksglist/sglist.c
diff --git a/include/uk/arch/types.h b/include/uk/arch/types.h
index 8b97baf..b108c8b 100644
--- a/include/uk/arch/types.h
+++ b/include/uk/arch/types.h
@@ -212,14 +212,17 @@ typedef __sptr __ssz; /* ssize_t equivalent */
typedef __sptr __off; /* off_t equivalent */
#if (defined __PHY_ADDR_IS_16)
+typedef __u16 __vm_offset;
typedef __u16 __phys_addr;
#define __PRIpaddr __PRIx16
#define __HAVE_PHYS_ADDR__
#elif (defined __PHY_ADDR_IS_32)
+typedef __u32 __vm_offset;
typedef __u32 __phys_addr;
#define __PRIpaddr __PRIx32
#define __HAVE_PHYS_ADDR__
#elif (defined __PHY_ADDR_IS_64)
+typedef __u64 __vm_offset;
typedef __u64 __phys_addr;
#define __PRIpaddr __PRIx64
#define __HAVE_PHYS_ADDR__
diff --git a/lib/Config.uk b/lib/Config.uk
index d0e614a..481d7ab 100644
--- a/lib/Config.uk
+++ b/lib/Config.uk
@@ -38,3 +38,4 @@ source "lib/uklock/Config.uk"
source "lib/ukmpi/Config.uk"
source "lib/ukswrand/Config.uk"
source "lib/ukbus/Config.uk"
+source "lib/uksglist/Config.uk"
diff --git a/lib/Makefile.uk b/lib/Makefile.uk
index 40c65d0..c7db848 100644
--- a/lib/Makefile.uk
+++ b/lib/Makefile.uk
@@ -19,3 +19,4 @@ $(eval $(call _import_lib,$(CONFIG_UK_BASE)/lib/vfscore))
$(eval $(call _import_lib,$(CONFIG_UK_BASE)/lib/uklock))
$(eval $(call _import_lib,$(CONFIG_UK_BASE)/lib/ukmpi))
$(eval $(call _import_lib,$(CONFIG_UK_BASE)/lib/ukbus))
+$(eval $(call _import_lib,$(CONFIG_UK_BASE)/lib/uksglist))
diff --git a/lib/uksglist/Config.uk b/lib/uksglist/Config.uk
new file mode 100644
index 0000000..ee967e4
--- /dev/null
+++ b/lib/uksglist/Config.uk
@@ -0,0 +1,8 @@
+menuconfig LIBUKSGLIST
+ bool "uksglist: Scatter Gather List"
+ default n
+ select LIBUKDEBUG
+ help
+ A scatter/gather list is a list of vectors, each of which gives
the
+ location and length of one segment in the overall
+ read or write request.
diff --git a/lib/uksglist/Makefile.uk b/lib/uksglist/Makefile.uk
new file mode 100644
index 0000000..3d7c21b
--- /dev/null
+++ b/lib/uksglist/Makefile.uk
@@ -0,0 +1,7 @@
+$(eval $(call addlib_s,libuksglist,$(CONFIG_LIBUKSGLIST)))
+
+CINCLUDES-$(CONFIG_LIBUKSGLIST) += -I$(LIBUKSGLIST_BASE)/include
+CXXINCLUDES-$(CONFIG_LIBUKSGLIST) += -I$(LIBUKSGLIST_BASE)/include
+
+LIBUKSGLIST_SRCS-y += $(LIBUKSGLIST_BASE)/sglist.c
+
diff --git a/lib/uksglist/exportsyms.uk b/lib/uksglist/exportsyms.uk
new file mode 100644
index 0000000..a1e9b37
--- /dev/null
+++ b/lib/uksglist/exportsyms.uk
@@ -0,0 +1,11 @@
+uk_sglist_count
+uk_sglist_alloc
+uk_sglist_free
+uk_sglist_append
+uk_sglist_append_sglist
+uk_sglist_build
+uk_sglist_clone
+uk_sglist_length
+uk_sglist_split
+uk_sglist_join
+uk_sglist_slice
diff --git a/lib/uksglist/include/uk/sglist.h b/lib/uksglist/include/uk/sglist.h
new file mode 100644
index 0000000..a89b10d
--- /dev/null
+++ b/lib/uksglist/include/uk/sglist.h
@@ -0,0 +1,272 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 2008 Yahoo!, Inc.
+ * All rights reserved.
+ * Written by: John Baldwin <jhb@xxxxxxxxxxx>
+ * Sharan Santhanam <sharan.santhanam@xxxxxxxxx>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the author nor the names of any co-contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+/**
+ * Taken and modified from FreeBSD
+ * Commit id: 4736ccfd9c34
+ */
+
+#ifndef UK__SGLIST_H__
+#define UK__SGLIST_H__
+
+#ifdef __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+
+#include <stdint.h>
+#include <uk/arch/types.h>
+#include <uk/refcount.h>
+#ifdef CONFIG_LIBUKALLOC
+#include <uk/alloc.h>
+#endif /* CONFIG_LIBUKALLOC */
+
+struct uk_sglist_seg {
+ __phys_addr ss_paddr; /* Physical address */
+ size_t ss_len; /* Length of the buffer */
+};
+
+struct uk_sglist {
+ struct uk_sglist_seg *sg_segs; /* Segment management */
+ __atomic sg_refs; /* Reference count for the sg list */
+ uint16_t sg_nseg; /* Number of segment in the sg list */
+ uint16_t sg_maxseg; /* Maximum number of segment in the sg list */
+};
+
+/**
+ * Initialize the sg list.
+ * @param sg
+ * A reference to sg list.
+ * @param maxsegs
+ * The max nr of segments.
+ * @param segs
+ * An array of segments.
+ */
+static inline void uk_sglist_init(struct uk_sglist *sg,
+ uint16_t maxsegs, struct uk_sglist_seg *segs)
+{
+ sg->sg_segs = segs;
+ sg->sg_nseg = 0;
+ sg->sg_maxseg = maxsegs;
+ uk_refcount_init(&sg->sg_refs, 1);
+}
+
+/**
+ * Reset the sg list.
+ * @param sg
+ * A reference to the sg list.
+ */
+static inline void uk_sglist_reset(struct uk_sglist *sg)
+{
+ sg->sg_nseg = 0;
+}
+
+/**
+ * Determine the number of scatter/gather list elements needed to describe a
+ * kernel virtual address range.
+ * @param buf
+ * The virtual address of the scatter gather list.
+ * @param len
+ * The size of the scatter gather list.
+ *
+ * @return
+ * - 0: The length was zero.
+ * - int: The number of segments
+ */
+int uk_sglist_count(void *buf, size_t len);
+
+/**
+ * Append the segments to describe a single kernel virtual address range to a
+ * scatter gather list.
+ *
+ * @param sg
+ * A reference to the scatter gather list.
+ * @param buf
+ * A reference to data buffer associated with the scatter gather list.
+ * @return
+ * - EINVAL: Invalid sg list.
+ * - EFBIG : Insufficient segments.
+ * - 0: Buffer was appended to the list.
+ */
+int uk_sglist_append(struct uk_sglist *sg, void *buf, size_t len);
+
+/**
+ * Append the subset of the sg list 'source' to sg list 'sg'.
+ *
+ * @param sg
+ * A reference to the update sg list.
+ * @param source
+ * A reference to the source sg list.
+ * @param offset
+ * The offset in the source from which th segment have to be copied.
+ * @param length
+ * The length to be copied.
+ * @return
+ * EINVAL: Invalid sg list or length parameter.
+ * EFBIG: Insufficient segments.
+ * 0 : Successful in appending subset of the list.
+ */
+int uk_sglist_append_sglist(struct uk_sglist *sg,
+ const struct uk_sglist *source,
+ size_t offset, size_t length);
+
+/**
+ * Calculate the total length of the segments described in a sg list.
+ * @param sg
+ * A reference to the sg list.
+ * @return
+ * size_t : The total length in the segments.
+ */
+size_t uk_sglist_length(struct uk_sglist *sg);
+
+/**
+ * Append the scatter/gather list elements in 'second' to the
+ * scatter/gather list 'first'.
+ * @param first
+ * The first sg list
+ * @param second
+ * The second sg list.
+ * @return
+ * EFBIG: Insufficient space.
+ * 0 : Successful joining of the list.
+ */
+int uk_sglist_join(struct uk_sglist *first, struct uk_sglist *second);
+
+#ifdef CONFIG_LIBUKALLOC
+/**
+ * Allocate a scatter/gather list along with 'nsegs' segments.
+ *
+ * @param a
+ * The allocator to allocate memory for the scatter gather list.
+ * @param nsegs
+ * The max number of segments.
+ * @return
+ * - NULL: Allocation failed.
+ * - (struct uk_sglist *): reference to scatter/gather list.
+ */
+struct uk_sglist *uk_sglist_alloc(struct uk_alloc *a, int nsegs);
+
+/**
+ * Free the scatter/gather list.
+ * @param sg
+ * A reference to the scatter gather list.
+ * @param a
+ * The allocator to allocate memory for the scatter gather list.
+ */
+void uk_sglist_free(struct uk_sglist *sg, struct uk_alloc *a);
+
+/**
+ * Allocate and populate a scatter/gather list to describe a single kernel
+ * virtual address range.
+ * @param a
+ * The allocator to used allocate the sg list.
+ * @param buf
+ * The virtual address of the buffer.
+ * @param len
+ * The length of the buffer.
+ * @return
+ * - NULL: Failed to create the sg list.
+ * - (struct uk_sglist *) reference to scatter/gather list.
+ */
+struct uk_sglist *uk_sglist_build(struct uk_alloc *a, void *buf,
+ size_t len);
+
+/**
+ * Clone a new copy of a scatter/gather list.
+ * @param sg
+ * A reference to the sg list to be cloned.
+ * @param a
+ * The allocator to use to allocate the sg list.
+ * @return
+ * NULL: Failed to clone the list.
+ * (struct uk_sglist *): reference to the sg list.
+ */
+struct uk_sglist *uk_sglist_clone(struct uk_sglist *sg,
+ struct uk_alloc *a);
+
+/**
+ * Split a scatter/gather list into two lists. The scatter/gather
+ * entries for the first 'length' bytes of the 'original' list are
+ * stored in the '*head' list and are removed from 'original'.
+ *
+ * @param original
+ * A reference to the sg list.
+ * @param head
+ * A reference to the head of the sg list. If NULL a new list will be
+ * allocated. If '*head' is not NULL, it should point to an empty sglist.
+ * @param a
+ * A reference to the allocator for maintaining the list.
+ * @param length
+ * The length of the list.
+ *
+ * @return
+ * EINVAL: Invalid sg list.
+ * ENOMEM: Allocation fails.
+ * EFBIG: Insufficient space.
+ * 0: Successful split of the list.
+ */
+int uk_sglist_split(struct uk_sglist *original, struct uk_sglist **head,
+ struct uk_alloc *a, size_t length);
+
+/**
+ * Generate a new scatter/gather list from a range of an existing
+ * scatter/gather list. The 'offset' and 'length' parameters specify
+ * the logical range of the 'original' list to extract.
+ *
+ * @param original
+ * The reference to a sg list to be extracted.
+ * @param slice
+ * If '*slice' is NULL, then a new list will be allocated.
+ * If '*slice' is not NULL, it should point to an empty sglist. If it
+ * does not have enough room for the remaining space
+ * @param a
+ * The allocator to be used.
+ * @param offset
+ * The offset from which the sglist had to be spliced.
+ * @param length
+ * The length of buffer in the original list.
+ * @return
+ * EINVAL: Invalid sg list.
+ * ENOMEM: No memory
+ * EFBIG: Insufficient space
+ * 0: Successful in splicing the list.
+ */
+int uk_sglist_slice(struct uk_sglist *original, struct uk_sglist **slice,
+ struct uk_alloc *a, size_t offset, size_t length);
+#endif /* CONFIG_LIBUKALLOC */
+
+#ifdef __cplusplus
+}
+#endif /* __cplusplus */
+
+#endif /* UK__SGLIST_H__ */
diff --git a/lib/uksglist/sglist.c b/lib/uksglist/sglist.c
new file mode 100644
index 0000000..0ec2105
--- /dev/null
+++ b/lib/uksglist/sglist.c
@@ -0,0 +1,533 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 2008 Yahoo!, Inc.
+ * All rights reserved.
+ * Written by: John Baldwin <jhb@xxxxxxxxxxx>
+ * Sharan Santhanam <sharan.santhanam@xxxxxxxxx>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the author nor the names of any co-contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+/**
+ * Taken and modified from FreeBSD
+ * Commit id: 4736ccfd9c34
+ */
+
+#include <errno.h>
+#include <string.h>
+#include <uk/plat/io.h>
+#include <uk/arch/types.h>
+#include <uk/arch/limits.h>
+#include <uk/refcount.h>
+#include <uk/assert.h>
+#ifdef CONFIG_LIBUKALLOC
+#include <uk/alloc.h>
+#endif /* CONFIG_LIBUKALLOC */
+#include <uk/sglist.h>
+
+/*
+ * Convenience macros to save the state of an sglist so it can be restored
+ * if an append attempt fails. Since sglist's only grow we only need to
+ * save the current count of segments and the length of the ending segment.
+ * Earlier segments will not be changed by an append, and the only change
+ * that can occur to the ending segment is that it can be extended.
+ */
+struct sgsave {
+ __u16 sg_nseg;
+ size_t ss_len;
+};
+
+#define page_off(x) ((unsigned long)(x) & (__PAGE_SIZE - 1))
+#define trunc_page(x) ((unsigned long)(x) & (__PAGE_MASK))
+
+#define SGLIST_SAVE(sg, sgsave) do {
\
+ (sgsave).sg_nseg = (sg)->sg_nseg; \
+ if ((sgsave).sg_nseg > 0) \
+ (sgsave).ss_len = (sg)->sg_segs[(sgsave).sg_nseg - 1].ss_len; \
+ else \
+ (sgsave).ss_len = 0; \
+} while (0)
+
+#define SGLIST_RESTORE(sg, sgsave) do {
\
+ (sg)->sg_nseg = (sgsave).sg_nseg; \
+ if ((sgsave).sg_nseg > 0) \
+ (sg)->sg_segs[(sgsave).sg_nseg - 1].ss_len = (sgsave).ss_len; \
+} while (0)
+
+static inline int _sglist_append_range(struct uk_sglist *sg,
+ struct uk_sglist_seg **ssp, __phys_addr paddr,
+ size_t len);
+static inline int _sglist_append_buf(struct uk_sglist *sg, void *buf,
+ size_t len, size_t *donep);
+/**
+ * Append a single (paddr, len) to a sglist. sg is the list and ss is
+ * the current segment in the list. If we run out of segments then
+ * EFBIG will be returned.
+ */
+static inline int _sglist_append_range(struct uk_sglist *sg,
+ struct uk_sglist_seg **ssp, __phys_addr paddr,
+ size_t len)
+{
+ struct uk_sglist_seg *ss;
+
+ ss = *ssp;
+ if (ss->ss_paddr + ss->ss_len == paddr)
+ ss->ss_len += len;
+ else {
+ if (sg->sg_nseg == sg->sg_maxseg)
+ return -EFBIG;
+ ss++;
+ ss->ss_paddr = paddr;
+ ss->ss_len = len;
+ sg->sg_nseg++;
+ *ssp = ss;
+ }
+ return 0;
+}
+
+/**
+ * Worker routine to append a virtual address range (either kernel or
+ * user) to a scatter/gather list.
+ */
+static inline int _sglist_append_buf(struct uk_sglist *sg, void *buf,
+ size_t len, size_t *donep)
+{
+ struct uk_sglist_seg *ss;
+ __vm_offset vaddr, offset;
+ __phys_addr paddr;
+ size_t seglen;
+ int error;
+
+ if (donep)
+ *donep = 0;
+ if (len == 0)
+ return 0;
+
+ /* Do the first page. It may have an offset. */
+ vaddr = (__vm_offset)buf;
+ offset = page_off(vaddr);
+ paddr = ukplat_virt_to_phys((void *)vaddr);
+ seglen = MIN(len, __PAGE_SIZE - offset);
+ if (sg->sg_nseg == 0) {
+ ss = sg->sg_segs;
+ ss->ss_paddr = paddr;
+ ss->ss_len = seglen;
+ sg->sg_nseg = 1;
+ } else {
+ ss = &sg->sg_segs[sg->sg_nseg - 1];
+ error = _sglist_append_range(sg, &ss, paddr, seglen);
+ if (error)
+ return error;
+ }
+ vaddr += seglen;
+ len -= seglen;
+ if (donep)
+ *donep += seglen;
+
+ while (len > 0) {
+ seglen = MIN(len, __PAGE_SIZE);
+ paddr = ukplat_virt_to_phys((void *)vaddr);
+ error = _sglist_append_range(sg, &ss, paddr, seglen);
+ if (error)
+ return error;
+ vaddr += seglen;
+ len -= seglen;
+ if (donep)
+ *donep += seglen;
+ }
+
+ return 0;
+}
+
+int uk_sglist_count(void *buf, size_t len)
+{
+ __vm_offset vaddr, vendaddr;
+ __phys_addr lastaddr, paddr;
+ int nsegs;
+
+ if (len == 0)
+ return 0;
+
+ vaddr = trunc_page((__vm_offset)buf);
+ vendaddr = (__vm_offset)buf + len;
+ nsegs = 1;
+ lastaddr = ukplat_virt_to_phys((void *)vaddr);
+ vaddr += __PAGE_SIZE;
+ while (vaddr < vendaddr) {
+ paddr = ukplat_virt_to_phys((void *)vaddr);
+ if (lastaddr + __PAGE_SIZE != paddr)
+ nsegs++;
+ lastaddr = paddr;
+ vaddr += __PAGE_SIZE;
+ }
+ return nsegs;
+}
+
+int uk_sglist_append(struct uk_sglist *sg, void *buf, size_t len)
+{
+ struct sgsave save;
+ int error;
+
+ UK_ASSERT(sg);
+
+ if (sg->sg_maxseg == 0)
+ return -EINVAL;
+
+ SGLIST_SAVE(sg, save);
+ error = _sglist_append_buf(sg, buf, len, NULL);
+ if (error)
+ SGLIST_RESTORE(sg, save);
+
+ return error;
+}
+
+int uk_sglist_append_sglist(struct uk_sglist *sg,
+ const struct uk_sglist *source,
+ size_t offset, size_t length)
+{
+ struct sgsave save;
+ struct uk_sglist_seg *ss;
+ size_t seglen;
+ int error, i;
+
+ UK_ASSERT(sg);
+
+ if (sg->sg_maxseg == 0 || length == 0)
+ return -EINVAL;
+ SGLIST_SAVE(sg, save);
+ error = -EINVAL;
+ ss = &sg->sg_segs[sg->sg_nseg - 1];
+ for (i = 0; i < source->sg_nseg; i++) {
+ if (offset >= source->sg_segs[i].ss_len) {
+ offset -= source->sg_segs[i].ss_len;
+ continue;
+ }
+ seglen = source->sg_segs[i].ss_len - offset;
+ if (seglen > length)
+ seglen = length;
+ error = _sglist_append_range(sg, &ss,
+ source->sg_segs[i].ss_paddr + offset, seglen);
+ if (error)
+ break;
+ offset = 0;
+ length -= seglen;
+ if (length == 0)
+ break;
+ }
+ if (length != 0) {
+ uk_pr_err("Failed to add buffer to the sg list\n");
+ error = -EINVAL;
+ }
+ if (error)
+ SGLIST_RESTORE(sg, save);
+ return error;
+}
+
+size_t uk_sglist_length(struct uk_sglist *sg)
+{
+ size_t space;
+ int i;
+
+ UK_ASSERT(sg);
+
+ space = 0;
+ for (i = 0; i < sg->sg_nseg; i++)
+ space += sg->sg_segs[i].ss_len;
+ return space;
+}
+
+int uk_sglist_join(struct uk_sglist *first, struct uk_sglist *second)
+{
+ struct uk_sglist_seg *flast, *sfirst;
+ int append;
+
+ /* If 'second' is empty, there is nothing to do. */
+ if (second->sg_nseg == 0)
+ return 0;
+
+ /*
+ * If the first entry in 'second' can be appended to the last entry
+ * in 'first' then set append to '1'.
+ */
+ append = 0;
+ flast = &first->sg_segs[first->sg_nseg - 1];
+ sfirst = &second->sg_segs[0];
+ if (first->sg_nseg != 0 &&
+ flast->ss_paddr + flast->ss_len == sfirst->ss_paddr)
+ append = 1;
+
+ /* Make sure 'first' has enough room. */
+ if (first->sg_nseg + second->sg_nseg - append > first->sg_maxseg)
+ return -EFBIG;
+
+ /* Merge last in 'first' and first in 'second' if needed. */
+ if (append)
+ flast->ss_len += sfirst->ss_len;
+
+ /* Append new segments from 'second' to 'first'. */
+ memmove(second->sg_segs + append, first->sg_segs + first->sg_nseg,
+ (second->sg_nseg - append) * sizeof(struct uk_sglist_seg));
+ first->sg_nseg += second->sg_nseg - append;
+ uk_sglist_reset(second);
+ return 0;
+}
+
+#ifdef CONFIG_UKALLOC
+struct uk_sglist *uk_sglist_alloc(struct uk_alloc *a, int nsegs)
+{
+ struct uk_sglist *sg;
+
+ UK_ASSERT(a);
+
+ /* Allocate the scatter/gather list */
+ sg = uk_malloc(a, sizeof(struct uk_sglist) +
+ (nsegs * sizeof(struct uk_sglist_seg)));
+ if (!sg) {
+ uk_pr_err("Error in allocating sg list\n");
+ return NULL;
+ }
+
+ /* Initialize the list */
+ uk_sglist_init(sg, nsegs, (struct uk_sglist_seg *)(sg + 1));
+ return sg;
+}
+
+void uk_sglist_free(struct uk_sglist *sg, struct uk_alloc *a)
+{
+ UK_ASSERT(sg && a);
+
+ if (uk_refcount_release(&sg->sg_refs))
+ uk_free(a, sg);
+}
+
+struct uk_sglist *uk_sglist_build(struct uk_alloc *a, void *buf,
+ size_t len)
+{
+ struct uk_sglist *sg;
+ int nsegs;
+
+ UK_ASSERT(a);
+
+ if (len == 0)
+ return NULL;
+
+ nsegs = uk_sglist_count(buf, len);
+ UK_ASSERT(nsegs > 0);
+
+ sg = uk_sglist_alloc(a, nsegs);
+ if (sg == NULL) {
+ uk_pr_err("Error in allocating the sg list\n");
+ return NULL;
+ }
+ if (uk_sglist_append(sg, buf, len) != 0) {
+ uk_pr_err("Error in adding segments to sg list\n");
+ uk_sglist_free(sg, a);
+ return NULL;
+ }
+ return sg;
+}
+
+struct uk_sglist *uk_sglist_clone(struct uk_sglist *sg,
+ struct uk_alloc *a)
+{
+ struct uk_sglist *new;
+
+ UK_ASSERT(a);
+
+ if (!sg)
+ return NULL;
+
+ new = uk_sglist_alloc(a, sg->sg_maxseg);
+ if (!new) {
+ uk_pr_err("Allocation for the new list failed\n");
+ return NULL;
+ }
+
+ new->sg_nseg = sg->sg_nseg;
+ memmove(new->sg_segs, sg->sg_segs,
+ sizeof(struct uk_sglist_seg) * sg->sg_nseg);
+ return new;
+}
+
+int uk_sglist_split(struct uk_sglist *original, struct uk_sglist **head,
+ struct uk_alloc *a, size_t length)
+{
+ struct uk_sglist *sg;
+ size_t space, split;
+ int count, i;
+
+ if (uk_refcount_read(&original->sg_refs) > 1)
+ return -EDOOFUS;
+
+ /* Figure out how big of a sglist '*head' has to hold. */
+ count = 0;
+ space = 0;
+ split = 0;
+ for (i = 0; i < original->sg_nseg; i++) {
+ space += original->sg_segs[i].ss_len;
+ count++;
+ if (space >= length) {
+ /*
+ * If 'length' falls in the middle of a
+ * scatter/gather list entry, then 'split'
+ * holds how much of that entry will remain in
+ * 'original'.
+ */
+ split = space - length;
+ break;
+ }
+ }
+
+ /* Nothing to do, so leave head empty. */
+ if (count == 0)
+ return 0;
+
+ if (*head == NULL) {
+ sg = uk_sglist_alloc(a, count);
+ if (sg == NULL)
+ return -ENOMEM;
+ *head = sg;
+ } else {
+ sg = *head;
+ if (sg->sg_maxseg < count)
+ return -EFBIG;
+ if (sg->sg_nseg != 0)
+ return -EINVAL;
+ }
+
+ /* Copy 'count' entries to 'sg' from 'original'. */
+ memmove(sg->sg_segs, original->sg_segs,
+ count * sizeof(struct uk_sglist_seg));
+ sg->sg_nseg = count;
+
+ /*
+ * If we had to split a list entry, fixup the last entry in
+ * 'sg' and the new first entry in 'original'. We also
+ * decrement 'count' by 1 since we will only be removing
+ * 'count - 1' segments from 'original' now.
+ */
+ if (split != 0) {
+ count--;
+ sg->sg_segs[count].ss_len -= split;
+ original->sg_segs[count].ss_paddr =
+ sg->sg_segs[count].ss_paddr + split;
+ original->sg_segs[count].ss_len = split;
+ }
+
+ /* Trim 'count' entries from the front of 'original'. */
+ original->sg_nseg -= count;
+ memmove(original->sg_segs, original->sg_segs + count,
+ count * sizeof(struct uk_sglist_seg));
+ return 0;
+}
+
+int uk_sglist_slice(struct uk_sglist *original, struct uk_sglist **slice,
+ struct uk_alloc *a, size_t offset, size_t length)
+{
+ struct uk_sglist *sg;
+ size_t space, end, foffs, loffs;
+ int count, i, fseg;
+
+ /* Nothing to do. */
+ if (length == 0)
+ return 0;
+
+ /* Figure out how many segments '*slice' needs to have. */
+ end = offset + length;
+ space = 0;
+ count = 0;
+ fseg = 0;
+ foffs = loffs = 0;
+ for (i = 0; i < original->sg_nseg; i++) {
+ space += original->sg_segs[i].ss_len;
+ if (space > offset) {
+ /*
+ * When we hit the first segment, store its index
+ * in 'fseg' and the offset into the first segment
+ * of 'offset' in 'foffs'.
+ */
+ if (count == 0) {
+ fseg = i;
+ foffs = offset - (space -
+ original->sg_segs[i].ss_len);
+ uk_pr_debug("sglist_slice: foffs = %08lx",
+ foffs);
+ }
+ count++;
+
+ /*
+ * When we hit the last segment, break out of
+ * the loop. Store the amount of extra space
+ * at the end of this segment in 'loffs'.
+ */
+ if (space >= end) {
+ loffs = space - end;
+ uk_pr_debug("sglist_slice: loffs = %08lx",
+ loffs);
+ break;
+ }
+ }
+ }
+
+ /* If we never hit 'end', then 'length' ran off the end, so fail. */
+ if (space < end)
+ return -EINVAL;
+
+ if (*slice == NULL) {
+ sg = uk_sglist_alloc(a, count);
+ if (sg == NULL)
+ return -ENOMEM;
+ *slice = sg;
+ } else {
+ sg = *slice;
+ if (sg->sg_maxseg < count)
+ return -EFBIG;
+ if (sg->sg_nseg != 0)
+ return -EINVAL;
+ }
+
+ /*
+ * Copy over 'count' segments from 'original' starting at
+ * 'fseg' to 'sg'.
+ */
+ memmove(sg->sg_segs, original->sg_segs + fseg,
+ count * sizeof(struct uk_sglist_seg));
+ sg->sg_nseg = count;
+
+ /* Fixup first and last segments if needed. */
+ if (foffs != 0) {
+ sg->sg_segs[0].ss_paddr += foffs;
+ sg->sg_segs[0].ss_len -= foffs;
+ uk_pr_debug("sglist_slice seg[0]: %16lx:%16lx",
+ (long)sg->sg_segs[0].ss_paddr, sg->sg_segs[0].ss_len);
+ }
+ if (loffs != 0) {
+ sg->sg_segs[count - 1].ss_len -= loffs;
+ uk_pr_debug("sglist_slice seg[%d]: len %08x",
+ count - 1, (uint32_t)sg->sg_segs[count - 1].ss_len);
+ }
+ return 0;
+}
+#endif /* CONFIG_UKALLOC */
--
2.7.4
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