Messages in this thread Patch in this message | | | Date | Wed, 7 Jul 2021 10:35:28 +0200 | From | Christoph Hellwig <> | Subject | Re: [ide] b7fb14d3ac: EIP:ioread32_rep |
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On Wed, Jul 07, 2021 at 10:12:20AM +0200, Christoph Hellwig wrote: > On Tue, Jul 06, 2021 at 12:08:42PM -0700, Linus Torvalds wrote: > > On Tue, Jul 6, 2021 at 7:36 AM Christoph Hellwig <hch@lst.de> wrote: > > > > > > Yeah, there's usually a huge offset into the page. The otherwise > > > similar ATAPI code actually has checks to chunk it up and not cross > > > page boundaries, and copying that over fixes the problem. > > > > Ok. > > > > Your patch made me go "I think it should loop until it has transferred > > the full 512 bytes", but maybe the caller loops properly? > > Yes, the callers (ata_read_pio_sectors) does).
Actually, not it doesn't. Sorry. So for a non-aligned large request this won't work. So we'll need to actually loop here.
This is probably better and fixes the issue as well (and ATAPI probably needs the same treatment):
diff --git a/drivers/ata/libata-sff.c b/drivers/ata/libata-sff.c index ae7189d1a568..40d2dc3b2989 100644 --- a/drivers/ata/libata-sff.c +++ b/drivers/ata/libata-sff.c @@ -637,6 +637,20 @@ unsigned int ata_sff_data_xfer32(struct ata_queued_cmd *qc, unsigned char *buf, } EXPORT_SYMBOL_GPL(ata_sff_data_xfer32); +static void ata_pio_xfer(struct ata_queued_cmd *qc, struct page *page, + unsigned int offset, size_t xfer_size) +{ + bool do_write = (qc->tf.flags & ATA_TFLAG_WRITE); + unsigned char *buf; + + buf = kmap_atomic(page); + qc->ap->ops->sff_data_xfer(qc, buf + offset, xfer_size, do_write); + kunmap_atomic(buf); + + if (!do_write && !PageSlab(page)) + flush_dcache_page(page); +} + /** * ata_pio_sector - Transfer a sector of data. * @qc: Command on going @@ -648,11 +662,9 @@ EXPORT_SYMBOL_GPL(ata_sff_data_xfer32); */ static void ata_pio_sector(struct ata_queued_cmd *qc) { - int do_write = (qc->tf.flags & ATA_TFLAG_WRITE); struct ata_port *ap = qc->ap; struct page *page; unsigned int offset; - unsigned char *buf; if (!qc->cursg) { qc->curbytes = qc->nbytes; @@ -670,13 +682,15 @@ static void ata_pio_sector(struct ata_queued_cmd *qc) DPRINTK("data %s\n", qc->tf.flags & ATA_TFLAG_WRITE ? "write" : "read"); - /* 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 (offset + qc->sect_size > PAGE_SIZE) { + unsigned int split_len = PAGE_SIZE - offset; - if (!do_write && !PageSlab(page)) - flush_dcache_page(page); + ata_pio_xfer(qc, page, offset, split_len); + ata_pio_xfer(qc, nth_page(page, 1), 0, + qc->sect_size - split_len); + } else { + ata_pio_xfer(qc, page, offset, qc->sect_size); + } qc->curbytes += qc->sect_size; qc->cursg_ofs += qc->sect_size;
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