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fs/aio: Stop allocating aio rings from HIGHMEM 

There is no need to allocate aio rings from HIGHMEM because of very
little memory needed here.

Therefore, use GFP_USER flag in find_or_create_page() and get rid of
kmap*() mappings.

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Ira Weiny <ira.weiny@intel.com>
Suggested-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Message-Id: <20230609145937.17610-1-fmdefrancesco@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
This commit is contained in:
Fabio M. De Francesco 2023-06-09 16:59:37 +02:00 committed by Christian Brauner
parent b6334e2cd4
commit 5c075c5b8f
1 changed files with 9 additions and 17 deletions
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26
fs/aio.c
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@ -530,7 +530,7 @@ static int aio_setup_ring(struct kioctx *ctx, unsigned int nr_events)
for (i = 0; i < nr_pages; i++) {
struct page *page;
page = find_or_create_page(file->f_mapping,
i, GFP_HIGHUSER | __GFP_ZERO);
i, GFP_USER | __GFP_ZERO);
if (!page)
break;
pr_debug("pid(%d) page[%d]->count=%d\n",
@ -571,7 +571,7 @@ static int aio_setup_ring(struct kioctx *ctx, unsigned int nr_events)
ctx->user_id = ctx->mmap_base;
ctx->nr_events = nr_events; /* trusted copy */
ring = kmap_atomic(ctx->ring_pages[0]);
ring = page_address(ctx->ring_pages[0]);
ring->nr = nr_events; /* user copy */
ring->id = ~0U;
ring->head = ring->tail = 0;
@ -579,7 +579,6 @@ static int aio_setup_ring(struct kioctx *ctx, unsigned int nr_events)
ring->compat_features = AIO_RING_COMPAT_FEATURES;
ring->incompat_features = AIO_RING_INCOMPAT_FEATURES;
ring->header_length = sizeof(struct aio_ring);
kunmap_atomic(ring);
flush_dcache_page(ctx->ring_pages[0]);
return 0;
@ -682,9 +681,8 @@ static int ioctx_add_table(struct kioctx *ctx, struct mm_struct *mm)
* we are protected from page migration
* changes ring_pages by ->ring_lock.
*/
ring = kmap_atomic(ctx->ring_pages[0]);
ring = page_address(ctx->ring_pages[0]);
ring->id = ctx->id;
kunmap_atomic(ring);
return 0;
}
@ -1025,9 +1023,8 @@ static void user_refill_reqs_available(struct kioctx *ctx)
* against ctx->completed_events below will make sure we do the
* safe/right thing.
*/
ring = kmap_atomic(ctx->ring_pages[0]);
ring = page_address(ctx->ring_pages[0]);
head = ring->head;
kunmap_atomic(ring);
refill_reqs_available(ctx, head, ctx->tail);
}
@ -1133,12 +1130,11 @@ static void aio_complete(struct aio_kiocb *iocb)
if (++tail >= ctx->nr_events)
tail = 0;
ev_page = kmap_atomic(ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE]);
ev_page = page_address(ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE]);
event = ev_page + pos % AIO_EVENTS_PER_PAGE;
*event = iocb->ki_res;
kunmap_atomic(ev_page);
flush_dcache_page(ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE]);
pr_debug("%p[%u]: %p: %p %Lx %Lx %Lx\n", ctx, tail, iocb,
@ -1152,10 +1148,9 @@ static void aio_complete(struct aio_kiocb *iocb)
ctx->tail = tail;
ring = kmap_atomic(ctx->ring_pages[0]);
ring = page_address(ctx->ring_pages[0]);
head = ring->head;
ring->tail = tail;
kunmap_atomic(ring);
flush_dcache_page(ctx->ring_pages[0]);
ctx->completed_events++;
@ -1215,10 +1210,9 @@ static long aio_read_events_ring(struct kioctx *ctx,
mutex_lock(&ctx->ring_lock);
/* Access to ->ring_pages here is protected by ctx->ring_lock. */
ring = kmap_atomic(ctx->ring_pages[0]);
ring = page_address(ctx->ring_pages[0]);
head = ring->head;
tail = ring->tail;
kunmap_atomic(ring);
/*
* Ensure that once we've read the current tail pointer, that
@ -1250,10 +1244,9 @@ static long aio_read_events_ring(struct kioctx *ctx,
avail = min(avail, nr - ret);
avail = min_t(long, avail, AIO_EVENTS_PER_PAGE - pos);
ev = kmap(page);
ev = page_address(page);
copy_ret = copy_to_user(event + ret, ev + pos,
sizeof(*ev) * avail);
kunmap(page);
if (unlikely(copy_ret)) {
ret = -EFAULT;
@ -1265,9 +1258,8 @@ static long aio_read_events_ring(struct kioctx *ctx,
head %= ctx->nr_events;
}
ring = kmap_atomic(ctx->ring_pages[0]);
ring = page_address(ctx->ring_pages[0]);
ring->head = head;
kunmap_atomic(ring);
flush_dcache_page(ctx->ring_pages[0]);
pr_debug("%li h%u t%u\n", ret, head, tail);