Commit 5d7a288c authored by Tycho Andersen's avatar Tycho Andersen Committed by Tejun Heo
Browse files

ata-sff: always map page before data transfer 

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: default avatarChristoph Hellwig <hch@infradead.org>
Signed-off-by: default avatarTycho Andersen <tycho@docker.com>
CC: Juerg Haefliger <juerg.haefliger@hpe.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent a95cfad9

drivers/ata/libata-sff.c

+8 −36
Original line number Diff line number Diff line
@@ -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);



	buf = kmap_atomic(page);

	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);

	}



	if (!do_write && !PageSlab(page))

		flush_dcache_page(page);
@@ -861,24 +847,10 @@ next_sg: 


	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);



	buf = kmap_atomic(page);

	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);

	}



	bytes -= min(bytes, consumed);

	qc->curbytes += count;

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