From bfd429ddd3bf54d7d6cd5d9ec64fca174e3c53eb Mon Sep 17 00:00:00 2001 From: "Luis R. Rodriguez" Date: Fri, 22 Mar 2013 19:33:38 +0000 Subject: [PATCH] compat: backport lib/scatterlist.c from 0db9299f Backport the lib/scatterlist.c addition, this required just removing the kmemleak stuff as that is not available on older kernels. mcgrof@frijol ~/linux-next (git::master)$ git describe --contains 0db9299f v2.6.25-rc1~1173^2~2 commit 0db9299f48ebd4a860d6ad4e1d36ac50671d48e7 Author: Jens Axboe Date: Fri Nov 30 09:16:50 2007 +0100 SG: Move functions to lib/scatterlist.c and add sg chaining allocator helpers Manually doing chained sg lists is not trivial, so add some helpers to make sure that drivers get it right. Signed-off-by: Jens Axboe 1 2.6.24 [ OK ] 2 2.6.25 [ OK ] 3 2.6.26 [ OK ] 4 2.6.27 [ OK ] 5 2.6.28 [ OK ] 6 2.6.29 [ OK ] 7 2.6.30 [ OK ] 8 2.6.31 [ OK ] 9 2.6.32 [ OK ] 10 2.6.33 [ OK ] 11 2.6.34 [ OK ] 12 2.6.35 [ OK ] 13 2.6.36 [ OK ] 14 2.6.37 [ OK ] 15 2.6.38 [ OK ] 16 2.6.39 [ OK ] 17 3.0.65 [ OK ] 18 3.1.10 [ OK ] 19 3.2.38 [ OK ] 20 3.3.8 [ OK ] 21 3.4.32 [ OK ] 22 3.5.7 [ OK ] 23 3.6.11 [ OK ] 24 3.7.9 [ OK ] 25 3.8.0 [ OK ] 26 3.9-rc1 [ OK ] Signed-off-by: Luis R. Rodriguez --- compat/compat-2.6.25.c | 191 ++++++++++++++++++++++++++++++++++ include/linux/compat-2.6.25.h | 33 ++++++ 2 files changed, 224 insertions(+) diff --git a/compat/compat-2.6.25.c b/compat/compat-2.6.25.c index 15500249d45a..20cc3dbd5fe0 100644 --- a/compat/compat-2.6.25.c +++ b/compat/compat-2.6.25.c @@ -11,6 +11,197 @@ #include #include +/* + * The default behaviour of sg_alloc_table() is to use these kmalloc/kfree + * helpers. + */ +static struct scatterlist *sg_kmalloc(unsigned int nents, gfp_t gfp_mask) +{ + if (nents == SG_MAX_SINGLE_ALLOC) { + return (struct scatterlist *) __get_free_page(gfp_mask); + } else + return kmalloc(nents * sizeof(struct scatterlist), gfp_mask); +} + +static void sg_kfree(struct scatterlist *sg, unsigned int nents) +{ + if (nents == SG_MAX_SINGLE_ALLOC) + free_page((unsigned long) sg); + else + kfree(sg); +} + + +/** + * __sg_free_table - Free a previously mapped sg table + * @table: The sg table header to use + * @max_ents: The maximum number of entries per single scatterlist + * @free_fn: Free function + * + * Description: + * Free an sg table previously allocated and setup with + * __sg_alloc_table(). The @max_ents value must be identical to + * that previously used with __sg_alloc_table(). + * + **/ +void __sg_free_table(struct sg_table *table, unsigned int max_ents, + sg_free_fn *free_fn) +{ + struct scatterlist *sgl, *next; + + if (unlikely(!table->sgl)) + return; + + sgl = table->sgl; + while (table->orig_nents) { + unsigned int alloc_size = table->orig_nents; + unsigned int sg_size; + + /* + * If we have more than max_ents segments left, + * then assign 'next' to the sg table after the current one. + * sg_size is then one less than alloc size, since the last + * element is the chain pointer. + */ + if (alloc_size > max_ents) { + next = sg_chain_ptr(&sgl[max_ents - 1]); + alloc_size = max_ents; + sg_size = alloc_size - 1; + } else { + sg_size = alloc_size; + next = NULL; + } + + table->orig_nents -= sg_size; + free_fn(sgl, alloc_size); + sgl = next; + } + + table->sgl = NULL; +} +EXPORT_SYMBOL(__sg_free_table); + +/** + * sg_free_table - Free a previously allocated sg table + * @table: The mapped sg table header + * + **/ +void sg_free_table(struct sg_table *table) +{ + __sg_free_table(table, SG_MAX_SINGLE_ALLOC, sg_kfree); +} +EXPORT_SYMBOL(sg_free_table); + +/** + * __sg_alloc_table - Allocate and initialize an sg table with given allocator + * @table: The sg table header to use + * @nents: Number of entries in sg list + * @max_ents: The maximum number of entries the allocator returns per call + * @gfp_mask: GFP allocation mask + * @alloc_fn: Allocator to use + * + * Description: + * This function returns a @table @nents long. The allocator is + * defined to return scatterlist chunks of maximum size @max_ents. + * Thus if @nents is bigger than @max_ents, the scatterlists will be + * chained in units of @max_ents. + * + * Notes: + * If this function returns non-0 (eg failure), the caller must call + * __sg_free_table() to cleanup any leftover allocations. + * + **/ +int __sg_alloc_table(struct sg_table *table, unsigned int nents, + unsigned int max_ents, gfp_t gfp_mask, + sg_alloc_fn *alloc_fn) +{ + struct scatterlist *sg, *prv; + unsigned int left; + +#ifndef ARCH_HAS_SG_CHAIN + if (WARN_ON_ONCE(nents > max_ents)) + return -EINVAL; +#endif + + memset(table, 0, sizeof(*table)); + + left = nents; + prv = NULL; + do { + unsigned int sg_size, alloc_size = left; + + if (alloc_size > max_ents) { + alloc_size = max_ents; + sg_size = alloc_size - 1; + } else + sg_size = alloc_size; + + left -= sg_size; + + sg = alloc_fn(alloc_size, gfp_mask); + if (unlikely(!sg)) { + /* + * Adjust entry count to reflect that the last + * entry of the previous table won't be used for + * linkage. Without this, sg_kfree() may get + * confused. + */ + if (prv) + table->nents = ++table->orig_nents; + + return -ENOMEM; + } + + sg_init_table(sg, alloc_size); + table->nents = table->orig_nents += sg_size; + + /* + * If this is the first mapping, assign the sg table header. + * If this is not the first mapping, chain previous part. + */ + if (prv) + sg_chain(prv, max_ents, sg); + else + table->sgl = sg; + + /* + * If no more entries after this one, mark the end + */ + if (!left) + sg_mark_end(&sg[sg_size - 1]); + + prv = sg; + } while (left); + + return 0; +} +EXPORT_SYMBOL(__sg_alloc_table); + +/** + * sg_alloc_table - Allocate and initialize an sg table + * @table: The sg table header to use + * @nents: Number of entries in sg list + * @gfp_mask: GFP allocation mask + * + * Description: + * Allocate and initialize an sg table. If @nents@ is larger than + * SG_MAX_SINGLE_ALLOC a chained sg table will be setup. + * + **/ +int sg_alloc_table(struct sg_table *table, unsigned int nents, gfp_t gfp_mask) +{ + int ret; + + ret = __sg_alloc_table(table, nents, SG_MAX_SINGLE_ALLOC, + gfp_mask, sg_kmalloc); + if (unlikely(ret)) + __sg_free_table(table, SG_MAX_SINGLE_ALLOC, sg_kfree); + + return ret; +} +EXPORT_SYMBOL(sg_alloc_table); + + /* * To backport b718989d correctly pcibios_enable_device() * is required but we don't have access to it on modules diff --git a/include/linux/compat-2.6.25.h b/include/linux/compat-2.6.25.h index a08e0b26ba34..dd986f5c6013 100644 --- a/include/linux/compat-2.6.25.h +++ b/include/linux/compat-2.6.25.h @@ -20,10 +20,43 @@ #include #include #include +#include #define __inet_lookup_established __inet_lookup_established_old #include #undef __inet_lookup_established #include + +struct sg_table { + struct scatterlist *sgl; /* the list */ + unsigned int nents; /* number of mapped entries */ + unsigned int orig_nents; /* original size of list */ +}; + +#define sg_alloc_fn LINUX_BACKPORT(sg_alloc_fn) +typedef struct scatterlist *(sg_alloc_fn)(unsigned int, gfp_t); + +#define sg_free_fn LINUX_BACKPORT(sg_free_fn) +typedef void (sg_free_fn)(struct scatterlist *, unsigned int); + +#define __sg_free_table LINUX_BACKPORT(__sg_free_table) +void __sg_free_table(struct sg_table *table, unsigned int max_ents, + sg_free_fn *free_fn); +#define sg_free_table LINUX_BACKPORT(sg_free_table) +void sg_free_table(struct sg_table *); +#define __sg_alloc_table LINUX_BACKPORT(__sg_alloc_table) +int __sg_alloc_table(struct sg_table *table, unsigned int nents, + unsigned int max_ents, gfp_t gfp_mask, + sg_alloc_fn *alloc_fn); +#define sg_alloc_table LINUX_BACKPORT(sg_alloc_table) +int sg_alloc_table(struct sg_table *table, unsigned int nents, gfp_t gfp_mask); + +/* + * Maximum number of entries that will be allocated in one piece, if + * a list larger than this is required then chaining will be utilized. + */ +#define SG_MAX_SINGLE_ALLOC (PAGE_SIZE / sizeof(struct scatterlist)) + + /* * Sockets in TCP_CLOSE state are _always_ taken out of the hash, so we need * not check it for lookups anymore, thanks Alexey. -DaveM -- 2.30.2