kernel/git/stable/linux.git/drivers/ata/libata-sff.c, branch master

ata: libata-sff: don't busy-wait for PIO data-in command completion

2026-07-20T23:55:31+00:00

Unlike PIO data-out, the PIO data-in protocol raises no completion interrupt, the last interrupt announces the final data block, and once the host has drained it from the data register the ending status must be obtained synchronously. ata_sff_hsm_move() does this by spinning in ata_wait_idle() for up to 10ms. Usually this is not a big deal unless the device is slow. In my case it's a CF card which keeps BSY asserted for multiple milliseconds(!) after the final data block. Since the waiting happens in the interrupt handler, under the port lock with interrupts disabled, the CPU is hogged for milliseconds on every read command. To improve the situation, bound the inline wait to ~100us. If the device is still busy after that, mark the command ATA_TFLAG_POLLING, so the interrupt handler won't race for it, and obtain the ending status via ata_sff_pio_task(), which sleeps between status checks instead of spinning with the lock held. Since ata_sff_pio_task() may now finish a data-in command, it must wait for both BSY and DRQ to clear at HSM_ST_LAST, matching what ata_wait_idle() enforced. Signed-off-by: Richard Weinberger Signed-off-by: Damien Le Moal

ata: libata: Document when host->eh_mutex should be held

2026-06-01T17:09:08+00:00

Annotate the following functions with __must_hold(&host->eh_mutex): * All ata_port_operations.error_handler() implementations. * ata_eh_reset() and ata_eh_recover() because these functions call ata_eh_release() and ata_eh_acquire(). * All callers of ata_eh_reset() and ata_eh_recover(). Enable Clang's context analysis. This will cause the build to fail if e.g. a locking bug would be introduced in an error path. This patch should not affect the generated assembler code. Signed-off-by: Bart Van Assche [cassel: drop note about clang 23 from commit log] Signed-off-by: Niklas Cassel

ata: libata-sff: add WQ_PERCPU to alloc_workqueue users

2025-11-07T08:42:36+00:00

Currently if a user enqueue a work item using schedule_delayed_work() the used wq is "system_wq" (per-cpu wq) while queue_delayed_work() use WORK_CPU_UNBOUND (used when a cpu is not specified). The same applies to schedule_work() that is using system_wq and queue_work(), that makes use again of WORK_CPU_UNBOUND. This lack of consistency cannot be addressed without refactoring the API. alloc_workqueue() treats all queues as per-CPU by default, while unbound workqueues must opt-in via WQ_UNBOUND. This default is suboptimal: most workloads benefit from unbound queues, allowing the scheduler to place worker threads where they’re needed and reducing noise when CPUs are isolated. This continues the effort to refactor workqueue APIs, which began with the introduction of new workqueues and a new alloc_workqueue flag in: commit 128ea9f6ccfb ("workqueue: Add system_percpu_wq and system_dfl_wq") commit 930c2ea566af ("workqueue: Add new WQ_PERCPU flag") This change adds a new WQ_PERCPU flag to explicitly request alloc_workqueue() to be per-cpu when WQ_UNBOUND has not been specified. With the introduction of the WQ_PERCPU flag (equivalent to !WQ_UNBOUND), any alloc_workqueue() caller that doesn’t explicitly specify WQ_UNBOUND must now use WQ_PERCPU. Once migration is complete, WQ_UNBOUND can be removed and unbound will become the implicit default. Suggested-by: Tejun Heo Signed-off-by: Marco Crivellari Reviewed-by: Damien Le Moal Signed-off-by: Niklas Cassel

ata: libata-sff: drop nth_page() usage within SG entry

2025-09-21T21:22:07+00:00

It's no longer required to use nth_page() when iterating pages within a single SG entry, so let's drop the nth_page() usage. Link: https://lkml.kernel.org/r/20250901150359.867252-26-david@redhat.com Signed-off-by: David Hildenbrand Acked-by: Damien Le Moal Reviewed-by: Lorenzo Stoakes Cc: Niklas Cassel Signed-off-by: Andrew Morton

ata: libata-eh: Simplify reset operation management

2025-07-16T07:31:43+00:00

Introduce struct ata_reset_operations to aggregate in a single structure the definitions of the 4 reset methods (prereset, softreset, hardreset and postreset) for a port. This new structure is used in struct ata_port to define the reset methods for a regular port (reset field) and for a port-multiplier port (pmp_reset field). A pointer to either of these fields replaces the 4 reset method arguments passed to ata_eh_recover() and ata_eh_reset(). The definition of the reset methods for all drivers is changed to use the reset and pmp_reset fields in struct ata_port_operations. A large number of files is modifed, but no functional changes are introduced. Suggested-by: Niklas Cassel Signed-off-by: Damien Le Moal Reviewed-by: Niklas Cassel Reviewed-by: Martin K. Petersen Reviewed-by: Hannes Reinecke Link: https://lore.kernel.org/r/20250716020315.235457-3-dlemoal@kernel.org Signed-off-by: Niklas Cassel

ata: libata-eh: Remove ata_do_eh()

2025-07-16T07:31:43+00:00

The only reason for ata_do_eh() to exist is that the two caller sites, ata_std_error_handler() and ata_sff_error_handler() may pass it a NULL hardreset operation so that the built-in (generic) hardreset operation for a driver is ignored if the adapter SCR access is not available. However, ata_std_error_handler() and ata_sff_error_handler() modifications of the hardreset port operation can easily be combined as they are mutually exclusive. That is, a driver using sata_std_hardreset() as its hardreset operation cannot use sata_sff_hardreset() and vice-versa. With this observation, ata_do_eh() can be removed and its code moved to ata_std_error_handler(). The condition used to ignore the built-in hardreset port operation is modified to be the one that was used in ata_sff_error_handler(). This requires defining a stub for the function sata_sff_hardreset() to avoid compilation errors when CONFIG_ATA_SFF is not enabled. Furthermore, instead of modifying the local hardreset operation definition, set the ATA_LFLAG_NO_HRST link flag to prevent the use of built-in hardreset methods for ports without a valid scr_read function. This flag is checked in ata_eh_reset() and if set, the hardreset method is ignored. This change simplifies ata_sff_error_handler() as this function now only needs to call ata_std_error_handler(). No functional changes. Signed-off-by: Damien Le Moal Reviewed-by: Niklas Cassel Reviewed-by: Martin K. Petersen Reviewed-by: Hannes Reinecke Link: https://lore.kernel.org/r/20250716020315.235457-2-dlemoal@kernel.org Signed-off-by: Niklas Cassel

ata: libata-sff: Ensure that we cannot write outside the allocated buffer

2025-01-28T10:44:47+00:00

reveliofuzzing reported that a SCSI_IOCTL_SEND_COMMAND ioctl with out_len set to 0xd42, SCSI command set to ATA_16 PASS-THROUGH, ATA command set to ATA_NOP, and protocol set to ATA_PROT_PIO, can cause ata_pio_sector() to write outside the allocated buffer, overwriting random memory. While a ATA device is supposed to abort a ATA_NOP command, there does seem to be a bug either in libata-sff or QEMU, where either this status is not set, or the status is cleared before read by ata_sff_hsm_move(). Anyway, that is most likely a separate bug. Looking at __atapi_pio_bytes(), it already has a safety check to ensure that __atapi_pio_bytes() cannot write outside the allocated buffer. Add a similar check to ata_pio_sector(), such that also ata_pio_sector() cannot write outside the allocated buffer. Cc: stable@vger.kernel.org Reported-by: reveliofuzzing Closes: https://lore.kernel.org/linux-ide/CA+-ZZ_jTgxh3bS7m+KX07_EWckSnW3N2adX3KV63y4g7M4CZ2A@mail.gmail.com/ Link: https://lore.kernel.org/r/20250127154303.15567-2-cassel@kernel.org Signed-off-by: Niklas Cassel

ata: libata: Remove ata_noop_qc_prep()

2024-08-02T00:18:42+00:00

The function ata_noop_qc_prep(), as its name implies, does nothing and simply returns AC_ERR_OK. For drivers that do not need any special preparations of queued commands, we can avoid having to define struct ata_port qc_prep operation by simply testing if that operation is defined or not in ata_qc_issue(). Make this change and remove ata_noop_qc_prep(). Signed-off-by: Damien Le Moal Reviewed-by: John Garry Reviewed-by: Sergey Shtylyov

ata: libata: Use QUIRK instead of HORKAGE

2024-07-29T22:09:54+00:00

According to Wiktionary, the verb "hork" is computing slang defined as "To foul up; to be occupied with difficulty, tangle, or unpleasantness; to be broken" (https://en.wiktionary.org/wiki/hork#Verb). libata uses this with the term "horkage" to refer to broken device features. Given that this term is not widely used and its meaning unknown to many, rename it to the more commonly used term "quirk", similar to many other places in the kernel. The renaming done is: 1) Rename all ATA_HORKAGE_XXX flags to ATA_QUIRK_XXX 2) Rename struct ata_device horkage field to quirks 3) Rename struct ata_blacklist_entry to struct ata_dev_quirks_entry. The array of these structures defining quirks for known devices is renamed __ata_dev_quirks. 4) The functions ata_dev_blacklisted() and ata_force_horkage() are renamed to ata_dev_quirks() and ata_force_quirks() respectively. 5) All the force_horkage_xxx() macros are renamed to force_quirk_xxx() And while at it, make sure that the type "unsigned int" is used consistantly for quirk flags variables and data structure fields. Signed-off-by: Damien Le Moal Reviewed-by: Niklas Cassel Reviewed-by: Igor Pylypiv

ata: add HAS_IOPORT dependencies

2024-04-08T01:07:28+00:00

In a future patch HAS_IOPORT=n will disable inb()/outb() and friends at compile time. We thus need to add HAS_IOPORT as dependency for those drivers using them. Co-developed-by: Arnd Bergmann Signed-off-by: Arnd Bergmann Signed-off-by: Niklas Schnelle Reviewed-by: Niklas Cassel Signed-off-by: Damien Le Moal