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ata-sff: always map page before data transfer

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The XPFO [1] patchset may unmap pages from physmap if they happened to be
destined for userspace. If such a page is unmapped, it needs to be
remapped. Rather than test if a page is in the highmem/xpfo unmapped state,
Christoph suggested [2] that we simply always map the page.

v2: * drop comment about bounce buffer
    * don't save IRQs before kmap/unmap
    * formatting

[1]: https://lkml.org/lkml/2016/11/4/245
[2]: https://lkml.org/lkml/2016/11/4/253

Suggested-and-reviewed-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Tycho Andersen <tycho@docker.com>
CC: Juerg Haefliger <juerg.haefliger@hpe.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Tycho Andersen 2017-05-04 16:15:51 -06:00 committed by Tejun Heo
parent a95cfad947
commit 5d7a288caf
1 changed files with 8 additions and 36 deletions
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44
drivers/ata/libata-sff.c
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@ -716,24 +716,10 @@ static void ata_pio_sector(struct ata_queued_cmd *qc)
DPRINTK("data %s\n", qc->tf.flags & ATA_TFLAG_WRITE ? "write" : "read");
if (PageHighMem(page)) {
unsigned long flags;
/* FIXME: use a bounce buffer */
local_irq_save(flags);
buf = kmap_atomic(page);
/* do the actual data transfer */
ap->ops->sff_data_xfer(qc, buf + offset, qc->sect_size,
do_write);
kunmap_atomic(buf);
local_irq_restore(flags);
} else {
buf = page_address(page);
ap->ops->sff_data_xfer(qc, buf + offset, qc->sect_size,
do_write);
}
/* do the actual data transfer */
buf = kmap_atomic(page);
ap->ops->sff_data_xfer(qc, buf + offset, qc->sect_size, do_write);
kunmap_atomic(buf);
if (!do_write && !PageSlab(page))
flush_dcache_page(page);
@ -861,24 +847,10 @@ static int __atapi_pio_bytes(struct ata_queued_cmd *qc, unsigned int bytes)
DPRINTK("data %s\n", qc->tf.flags & ATA_TFLAG_WRITE ? "write" : "read");
if (PageHighMem(page)) {
unsigned long flags;
/* FIXME: use bounce buffer */
local_irq_save(flags);
buf = kmap_atomic(page);
/* do the actual data transfer */
consumed = ap->ops->sff_data_xfer(qc, buf + offset,
count, rw);
kunmap_atomic(buf);
local_irq_restore(flags);
} else {
buf = page_address(page);
consumed = ap->ops->sff_data_xfer(qc, buf + offset,
count, rw);
}
/* do the actual data transfer */
buf = kmap_atomic(page);
consumed = ap->ops->sff_data_xfer(qc, buf + offset, count, rw);
kunmap_atomic(buf);
bytes -= min(bytes, consumed);
qc->curbytes += count;