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xfs: merge _xfs_buf_get_pages()
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Only called from one place now, so merge it into
xfs_buf_alloc_pages(). Because page array allocation is dependent on
bp->b_pages being null, always ensure that when the pages array is
freed we always set bp->b_pages to null.

Also convert the page array to use kmalloc() rather than
kmem_alloc() so we can use the gfp flags we've already calculated
for the allocation context instead of hard coding KM_NOFS semantics.

Signed-off-by: Dave Chinner <[email protected]>
Reviewed-by: Darrick J. Wong <[email protected]>
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Dave Chinner authored and dchinner committed Jun 1, 2021
1 parent c9fa563 commit 02c5117
Showing 1 changed file with 14 additions and 34 deletions.
48 changes: 14 additions & 34 deletions fs/xfs/xfs_buf.c
Original file line number Diff line number Diff line change
Expand Up @@ -272,42 +272,16 @@ _xfs_buf_alloc(
return 0;
}

/*
* Allocate a page array capable of holding a specified number
* of pages, and point the page buf at it.
*/
STATIC int
_xfs_buf_get_pages(
struct xfs_buf *bp,
int page_count)
{
/* Make sure that we have a page list */
if (bp->b_pages == NULL) {
bp->b_page_count = page_count;
if (page_count <= XB_PAGES) {
bp->b_pages = bp->b_page_array;
} else {
bp->b_pages = kmem_alloc(sizeof(struct page *) *
page_count, KM_NOFS);
if (bp->b_pages == NULL)
return -ENOMEM;
}
memset(bp->b_pages, 0, sizeof(struct page *) * page_count);
}
return 0;
}

/*
* Frees b_pages if it was allocated.
*/
STATIC void
_xfs_buf_free_pages(
struct xfs_buf *bp)
{
if (bp->b_pages != bp->b_page_array) {
if (bp->b_pages != bp->b_page_array)
kmem_free(bp->b_pages);
bp->b_pages = NULL;
}
bp->b_pages = NULL;
}

/*
Expand Down Expand Up @@ -389,16 +363,22 @@ xfs_buf_alloc_pages(
long filled = 0;
int error;

/* Make sure that we have a page list */
bp->b_page_count = page_count;
if (bp->b_page_count <= XB_PAGES) {
bp->b_pages = bp->b_page_array;
} else {
bp->b_pages = kzalloc(sizeof(struct page *) * bp->b_page_count,
gfp_mask);
if (!bp->b_pages)
return -ENOMEM;
}
bp->b_flags |= _XBF_PAGES;

/* Assure zeroed buffer for non-read cases. */
if (!(flags & XBF_READ))
gfp_mask |= __GFP_ZERO;

error = _xfs_buf_get_pages(bp, page_count);
if (unlikely(error))
return error;

bp->b_flags |= _XBF_PAGES;

/*
* Bulk filling of pages can take multiple calls. Not filling the entire
* array is not an allocation failure, so don't back off if we get at
Expand Down

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