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abd_os: split userspace and Linux kernel code

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The Linux abd_os.c serves double-duty as the userspace scatter abd
implementation, by carrying an emulation of kernel scatterlists. This
commit lifts common and userspace-specific parts out into a separate
abd_os.c for libzpool.

Sponsored-by: Klara, Inc.
Sponsored-by: Wasabi Technology, Inc.
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Rob Norris <rob.norris@klarasystems.com>
Closes #16253
This commit is contained in:
Rob Norris
2023-12-25 22:25:48 +11:00
committed by Brian Behlendorf
parent 2b7d9a7863
commit 7a5b4355e2
4 changed files with 498 additions and 149 deletions
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module/os/linux/zfs/abd_os.c
+3 -148
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@@ -58,22 +58,16 @@
#include <sys/arc.h>
#include <sys/zfs_context.h>
#include <sys/zfs_znode.h>
#ifdef _KERNEL
#include <linux/kmap_compat.h>
#include <linux/mm_compat.h>
#include <linux/scatterlist.h>
#include <linux/version.h>
#endif
#ifdef _KERNEL
#if defined(MAX_ORDER)
#define ABD_MAX_ORDER (MAX_ORDER)
#elif defined(MAX_PAGE_ORDER)
#define ABD_MAX_ORDER (MAX_PAGE_ORDER)
#endif
#else
#define ABD_MAX_ORDER (1)
#endif
typedef struct abd_stats {
kstat_named_t abdstat_struct_size;
@@ -193,11 +187,9 @@ abd_t *abd_zero_scatter = NULL;
struct page;
/*
* _KERNEL - Will point to ZERO_PAGE if it is available or it will be
* an allocated zero'd PAGESIZE buffer.
* Userspace - Will be an allocated zero'ed PAGESIZE buffer.
*
* abd_zero_page is assigned to each of the pages of abd_zero_scatter.
* abd_zero_page is assigned to each of the pages of abd_zero_scatter. It will
* point to ZERO_PAGE if it is available or it will be an allocated zero'd
* PAGESIZE buffer.
*/
static struct page *abd_zero_page = NULL;
@@ -232,7 +224,6 @@ abd_free_struct_impl(abd_t *abd)
ABDSTAT_INCR(abdstat_struct_size, -(int)sizeof (abd_t));
}
#ifdef _KERNEL
static unsigned zfs_abd_scatter_max_order = ABD_MAX_ORDER - 1;
/*
@@ -520,134 +511,6 @@ abd_alloc_zero_scatter(void)
ABDSTAT_BUMP(abdstat_scatter_page_multi_chunk);
}
#else /* _KERNEL */
#ifndef PAGE_SHIFT
#define PAGE_SHIFT (highbit64(PAGESIZE)-1)
#endif
#define zfs_kmap_local(chunk) ((void *)chunk)
#define zfs_kunmap_local(addr) do { (void)(addr); } while (0)
#define local_irq_save(flags) do { (void)(flags); } while (0)
#define local_irq_restore(flags) do { (void)(flags); } while (0)
#define nth_page(pg, i) \
((struct page *)((void *)(pg) + (i) * PAGESIZE))
struct scatterlist {
struct page *page;
int length;
int end;
};
static void
sg_init_table(struct scatterlist *sg, int nr)
{
memset(sg, 0, nr * sizeof (struct scatterlist));
sg[nr - 1].end = 1;
}
/*
* This must be called if any of the sg_table allocation functions
* are called.
*/
static void
abd_free_sg_table(abd_t *abd)
{
int nents = ABD_SCATTER(abd).abd_nents;
vmem_free(ABD_SCATTER(abd).abd_sgl,
nents * sizeof (struct scatterlist));
}
#define for_each_sg(sgl, sg, nr, i) \
for ((i) = 0, (sg) = (sgl); (i) < (nr); (i)++, (sg) = sg_next(sg))
static inline void
sg_set_page(struct scatterlist *sg, struct page *page, unsigned int len,
unsigned int offset)
{
/* currently we don't use offset */
ASSERT(offset == 0);
sg->page = page;
sg->length = len;
}
static inline struct page *
sg_page(struct scatterlist *sg)
{
return (sg->page);
}
static inline struct scatterlist *
sg_next(struct scatterlist *sg)
{
if (sg->end)
return (NULL);
return (sg + 1);
}
void
abd_alloc_chunks(abd_t *abd, size_t size)
{
unsigned nr_pages = abd_chunkcnt_for_bytes(size);
struct scatterlist *sg;
int i;
ABD_SCATTER(abd).abd_sgl = vmem_alloc(nr_pages *
sizeof (struct scatterlist), KM_SLEEP);
sg_init_table(ABD_SCATTER(abd).abd_sgl, nr_pages);
abd_for_each_sg(abd, sg, nr_pages, i) {
struct page *p = umem_alloc_aligned(PAGESIZE, 64, KM_SLEEP);
sg_set_page(sg, p, PAGESIZE, 0);
}
ABD_SCATTER(abd).abd_nents = nr_pages;
}
void
abd_free_chunks(abd_t *abd)
{
int i, n = ABD_SCATTER(abd).abd_nents;
struct scatterlist *sg;
abd_for_each_sg(abd, sg, n, i) {
struct page *p = nth_page(sg_page(sg), 0);
umem_free_aligned(p, PAGESIZE);
}
abd_free_sg_table(abd);
}
static void
abd_alloc_zero_scatter(void)
{
unsigned nr_pages = abd_chunkcnt_for_bytes(SPA_MAXBLOCKSIZE);
struct scatterlist *sg;
int i;
abd_zero_page = umem_alloc_aligned(PAGESIZE, 64, KM_SLEEP);
memset(abd_zero_page, 0, PAGESIZE);
abd_zero_scatter = abd_alloc_struct(SPA_MAXBLOCKSIZE);
abd_zero_scatter->abd_flags |= ABD_FLAG_OWNER;
abd_zero_scatter->abd_flags |= ABD_FLAG_MULTI_CHUNK | ABD_FLAG_ZEROS;
ABD_SCATTER(abd_zero_scatter).abd_offset = 0;
ABD_SCATTER(abd_zero_scatter).abd_nents = nr_pages;
abd_zero_scatter->abd_size = SPA_MAXBLOCKSIZE;
ABD_SCATTER(abd_zero_scatter).abd_sgl = vmem_alloc(nr_pages *
sizeof (struct scatterlist), KM_SLEEP);
sg_init_table(ABD_SCATTER(abd_zero_scatter).abd_sgl, nr_pages);
abd_for_each_sg(abd_zero_scatter, sg, nr_pages, i) {
sg_set_page(sg, abd_zero_page, PAGESIZE, 0);
}
ABDSTAT_BUMP(abdstat_scatter_cnt);
ABDSTAT_INCR(abdstat_scatter_data_size, PAGESIZE);
ABDSTAT_BUMP(abdstat_scatter_page_multi_chunk);
}
#endif /* _KERNEL */
boolean_t
abd_size_alloc_linear(size_t size)
{
@@ -712,14 +575,10 @@ abd_free_zero_scatter(void)
abd_free_struct(abd_zero_scatter);
abd_zero_scatter = NULL;
ASSERT3P(abd_zero_page, !=, NULL);
#if defined(_KERNEL)
#if defined(HAVE_ZERO_PAGE_GPL_ONLY)
abd_unmark_zfs_page(abd_zero_page);
__free_page(abd_zero_page);
#endif /* HAVE_ZERO_PAGE_GPL_ONLY */
#else
umem_free_aligned(abd_zero_page, PAGESIZE);
#endif /* _KERNEL */
}
static int
@@ -1014,8 +873,6 @@ abd_cache_reap_now(void)
{
}
#if defined(_KERNEL)
/*
* This is abd_iter_page(), the function underneath abd_iterate_page_func().
* It yields the next page struct and data offset and size within it, without
@@ -1297,5 +1154,3 @@ MODULE_PARM_DESC(zfs_abd_scatter_min_size,
module_param(zfs_abd_scatter_max_order, uint, 0644);
MODULE_PARM_DESC(zfs_abd_scatter_max_order,
"Maximum order allocation used for a scatter ABD.");
#endif /* _KERNEL */