libata-sff: fix 32-bit PIO ATAPI regression (d1b3525b) · Commits · 戴 / test

Commit (libata: Add 32bit PIO support) has caused all kinds of errors on the ATAPI devices, so it has been empirically proven that one shouldn't try to read/write an extra data word when a device is not expecting it already. "Don't do it then"; however, still use a chance to do 32-bit read/write one last time when there are exactly 3 trailing bytes. Oh, and stop pointlessly swapping the bytes to and fro on big-endian machines by using io*_rep() accessors which shouldn't byte-swap. This patch should fix the kernel.org bug #12609. Signed-off-by:

Sergei Shtylyov <sshtylyov@ru.mvista.com> Signed-off-by:

Jeff Garzik <jgarzik@redhat.com>

drivers/ata/libata-sff.c

+21 −7

Original line number	Diff line number	Diff line
		@@ -773,18 +773,32 @@ unsigned int ata_sff_data_xfer32(struct ata_device dev, unsigned char buf,
		else
		iowrite32_rep(data_addr, buf, words);

		/* Transfer trailing bytes, if any */
		if (unlikely(slop)) {
		__le32 pad;
		unsigned char pad[4];

		/* Point buf to the tail of buffer */
		buf += buflen - slop;

		/*
		* Use io*_rep() accessors here as well to avoid pointlessly
		* swapping bytes to and fro on the big endian machines...
		*/
		if (rw == READ) {
		pad = cpu_to_le32(ioread32(ap->ioaddr.data_addr));
		memcpy(buf + buflen - slop, &pad, slop);
		if (slop < 3)
		ioread16_rep(data_addr, pad, 1);
		else
		ioread32_rep(data_addr, pad, 1);
		memcpy(buf, pad, slop);
		} else {
		memcpy(&pad, buf + buflen - slop, slop);
		iowrite32(le32_to_cpu(pad), ap->ioaddr.data_addr);
		memcpy(pad, buf, slop);
		if (slop < 3)
		iowrite16_rep(data_addr, pad, 1);
		else
		iowrite32_rep(data_addr, pad, 1);
		}
		words++;
		}
		return words << 2;
		return (buflen + 1) & ~1;
		}
		EXPORT_SYMBOL_GPL(ata_sff_data_xfer32);

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