[PATCH 5.4 402/411] ata: libata-transport: fix {dma|pio|xfer}_mode sysfs files

Greg Kroah-Hartman
2022-06-13T11:53:03Z

From: Sergey Shtylyov <s.shtylyov@omp.ru>

commit 72aad489f992871e908ff6d9055b26c6366fb864 upstream.

The {dma|pio}_mode sysfs files are incorrectly documented as having a
list of the supported DMA/PIO transfer modes, while the corresponding
fields of the *struct* ata_device hold the transfer mode IDs, not masks.

To match these docs, the {dma|pio}_mode (and even xfer_mode!) sysfs
files are handled by the ata_bitfield_name_match() macro which leads to
reading such kind of nonsense from them:

$ cat /sys/class/ata_device/dev3.0/pio_mode
XFER_UDMA_7, XFER_UDMA_6, XFER_UDMA_5, XFER_UDMA_4, XFER_MW_DMA_4,
XFER_PIO_6, XFER_PIO_5, XFER_PIO_4, XFER_PIO_3, XFER_PIO_2, XFER_PIO_1,
XFER_PIO_0

Using the correct ata_bitfield_name_search() macro fixes that:

$ cat /sys/class/ata_device/dev3.0/pio_mode
XFER_PIO_4

While fixing the file documentation, somewhat reword the {dma|pio}_mode
file doc and add a note about being mostly useful for PATA devices to
the xfer_mode file doc...

Fixes: d9027470b886 ("[libata] Add ATA transport class")
Signed-off-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Cc: stable@vger.kernel.org
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
Documentation/ABI/testing/sysfs-ata | 11 ++++++-----
drivers/ata/libata-transport.c | 2 +-
2 files changed, 7 insertions(+), 6 deletions(-)

--- a/Documentation/ABI/testing/sysfs-ata
+++ b/Documentation/ABI/testing/sysfs-ata
@@ -107,13 +107,14 @@ Description:
described in ATA8 7.16 and 7.17. Only valid if
the device is not a PM.

- pio_mode: (RO) Transfer modes supported by the device when
- in PIO mode. Mostly used by PATA device.
+ pio_mode: (RO) PIO transfer mode used by the device.
+ Mostly used by PATA devices.

- xfer_mode: (RO) Current transfer mode
+ xfer_mode: (RO) Current transfer mode. Mostly used by
+ PATA devices.

- dma_mode: (RO) Transfer modes supported by the device when
- in DMA mode. Mostly used by PATA device.
+ dma_mode: (RO) DMA transfer mode used by the device.
+ Mostly used by PATA devices.

class: (RO) Device class. Can be "ata" for disk,
"atapi" for packet device, "pmp" for PM, or
--- a/drivers/ata/libata-transport.c
+++ b/drivers/ata/libata-transport.c
@@ -196,7 +196,7 @@ static struct {
{ XFER_PIO_0, "XFER_PIO_0" },
{ XFER_PIO_SLOW, "XFER_PIO_SLOW" }
};
-ata_bitfield_name_match(xfer,ata_xfer_names)
+ata_bitfield_name_search(xfer, ata_xfer_names)

/*
* ATA Port attributes