On Mon, Sep 02, 2024 at 08:54:00PM +0900, Damien Le Moal wrote:
> The ncq_sense_buf buffer field of struct ata_port is allocated and used
> only for devices that support the Command Duration Limits (CDL) feature.
> However, the cdl buffer of struct ata_device, which is used to cache the
> command duration limits log page for devices supporting CDL is always
> allocated as part of struct ata_device, which is wasteful of memory for
> devices that do not support this feature.
>
> Clean this up by defining both buffers as part of the new ata_cdl
> structure and allocating this structure only for devices that support
> the CDL feature. This new structure is attached to struct ata_device
> using the cdl pointer.
>
> The functions ata_dev_init_cdl_resources() and
> ata_dev_cleanup_cdl_resources() are defined to manage this new structure
> allocation, initialization and cleanup when a port is removed or a
> device disabled. ata_dev_init_cdl_resources() is called from
> ata_dev_config_cdl() only for devices that support CDL.
> ata_dev_cleanup_cdl_resources() is called from ata_port_free() and
> ata_eh_dev_disable() to free the ata_cdl structure when a device is
> being disabled by EH or its port being removed.
>
> Note that the name of the former cdl log buffer of struct ata_device is
> changed to desc_log_buf to make it clearer that it is a buffer for the
> limit descriptors log page.
>
> This change reduces the size of struct ata_device, thus reducing memory
> usage for ATA devices that do not support the CDL feature.
>
> Signed-off-by: Damien Le Moal <dlemoal@xxxxxxxxxx>
> Reviewed-by: Hannes Reinecke <hare@xxxxxxx>
> ---
> drivers/ata/libata-core.c | 74 ++++++++++++++++++++++++++-------------
> drivers/ata/libata-eh.c | 2 ++
> drivers/ata/libata-sata.c | 2 +-
> drivers/ata/libata-scsi.c | 2 +-
> drivers/ata/libata.h | 1 +
> include/linux/libata.h | 21 ++++++++---
> 6 files changed, 72 insertions(+), 30 deletions(-)
>
> diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
> index 32325a1c07af..428931a0cb8d 100644
> --- a/drivers/ata/libata-core.c
> +++ b/drivers/ata/libata-core.c
> @@ -2464,12 +2464,40 @@ static void ata_dev_config_trusted(struct ata_device *dev)
> dev->flags |= ATA_DFLAG_TRUSTED;
> }
>
> +static int ata_dev_init_cdl_resources(struct ata_device *dev)
> +{
> + struct ata_cdl *cdl = dev->cdl;
> + unsigned int err_mask;
> +
> + if (!cdl) {
> + cdl = kzalloc(sizeof(struct ata_cdl), GFP_KERNEL);
cdl = kzalloc(sizeof(*ata_cdl), GFP_KERNEL);
is more robust, as with the current code, if someone changes type of *cdl,
there is a chance to introduce a bug if they forget to update this line.
> + if (!cdl)
> + return -ENOMEM;
> + dev->cdl = cdl;
> + }
> +
> + err_mask = ata_read_log_page(dev, ATA_LOG_CDL, 0, cdl->desc_log_buf,
> + ATA_LOG_CDL_SIZE / ATA_SECT_SIZE);
> + if (err_mask) {
> + ata_dev_warn(dev, "Read Command Duration Limits log failed\n");
> + return -EIO;
> + }
> +
> + return 0;
> +}
> +
> +void ata_dev_cleanup_cdl_resources(struct ata_device *dev)
> +{
> + kfree(dev->cdl);
> + dev->cdl = NULL;
> +}
> +
> static void ata_dev_config_cdl(struct ata_device *dev)
> {
> - struct ata_port *ap = dev->link->ap;
> unsigned int err_mask;
> bool cdl_enabled;
> u64 val;
> + int ret;
>
> if (ata_id_major_version(dev->id) < 11)
> goto not_supported;
> @@ -2564,37 +2592,20 @@ static void ata_dev_config_cdl(struct ata_device *dev)
> }
> }
>
> - /*
> - * Allocate a buffer to handle reading the sense data for successful
> - * NCQ Commands log page for commands using a CDL with one of the limit
> - * policy set to 0xD (successful completion with sense data available
> - * bit set).
> - */
> - if (!ap->ncq_sense_buf) {
> - ap->ncq_sense_buf = kmalloc(ATA_LOG_SENSE_NCQ_SIZE, GFP_KERNEL);
> - if (!ap->ncq_sense_buf)
> - goto not_supported;
> - }
> -
> - /*
> - * Command duration limits is supported: cache the CDL log page 18h
> - * (command duration descriptors).
> - */
> - err_mask = ata_read_log_page(dev, ATA_LOG_CDL, 0, dev->sector_buf, 1);
> - if (err_mask) {
> - ata_dev_warn(dev, "Read Command Duration Limits log failed\n");
> + /* CDL is supported: allocate and initialize needed resources. */
> + ret = ata_dev_init_cdl_resources(dev);
> + if (ret) {
> + ata_dev_warn(dev, "Initialize CDL resources failed\n");
> goto not_supported;
> }
>
> - memcpy(dev->cdl, dev->sector_buf, ATA_LOG_CDL_SIZE);
> dev->flags |= ATA_DFLAG_CDL;
>
> return;
>
> not_supported:
> dev->flags &= ~(ATA_DFLAG_CDL | ATA_DFLAG_CDL_ENABLED);
> - kfree(ap->ncq_sense_buf);
> - ap->ncq_sense_buf = NULL;
> + ata_dev_cleanup_cdl_resources(dev);
> }
>
> static int ata_dev_config_lba(struct ata_device *dev)
> @@ -5446,12 +5457,19 @@ EXPORT_SYMBOL_GPL(ata_port_alloc);
>
> void ata_port_free(struct ata_port *ap)
> {
> + struct ata_device *dev;
> + struct ata_link *link;
> +
> if (!ap)
> return;
>
> + ata_for_each_link(link, ap, HOST_FIRST) {
> + ata_for_each_dev(dev, link, ALL)
> + ata_dev_cleanup_cdl_resources(dev);
> + }
Here you free the resources when the port is freed, nice.
> +
> kfree(ap->pmp_link);
> kfree(ap->slave_link);
> - kfree(ap->ncq_sense_buf);
> ida_free(&ata_ida, ap->print_id);
> kfree(ap);
> }
> @@ -6000,11 +6018,19 @@ static void ata_port_detach(struct ata_port *ap)
> ata_port_wait_eh(ap);
>
> mutex_lock(&ap->scsi_scan_mutex);
> +
> + /* Cleanup CDL device resources */
> + ata_for_each_link(link, ap, HOST_FIRST) {
> + ata_for_each_dev(dev, link, ALL)
> + ata_dev_cleanup_cdl_resources(dev);
Here you clean up resources.
Why?
Resources will get cleaned up when ata_port_free() is called,
which will be called by ata_devres_release() -> ata_host_put()
-> ata_host_release() -> ata_port_free(), when the device is
removed.
I don't see any reason to free it here as well.
That will just ensure that the ata_dev_cleanup_cdl_resources()
call by ata_port_free() will do nothing.
> + }
> +
> spin_lock_irqsave(ap->lock, flags);
>
> /* Remove scsi devices */
> ata_for_each_link(link, ap, HOST_FIRST) {
> ata_for_each_dev(dev, link, ALL) {
> + ata_dev_cleanup_cdl_resources(dev);
What is the point of this call?
You already looped through all devices in this same function
(ata_port_detach()) just above.
But just like my comment above, I don't see any reason to call
ata_dev_cleanup_cdl_resources() here. The resources will get
freed by ata_port_free() when the device is removed.
I think you can remove both ata_dev_cleanup_cdl_resources()
calls in ata_port_detach().
> if (dev->sdev) {
> spin_unlock_irqrestore(ap->lock, flags);
> scsi_remove_device(dev->sdev);
> diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
> index ed535e1b4225..41f1bee0b434 100644
> --- a/drivers/ata/libata-eh.c
> +++ b/drivers/ata/libata-eh.c
> @@ -500,6 +500,8 @@ static void ata_eh_dev_disable(struct ata_device *dev)
> ata_down_xfermask_limit(dev, ATA_DNXFER_FORCE_PIO0 | ATA_DNXFER_QUIET);
> dev->class++;
>
> + ata_dev_cleanup_cdl_resources(dev);
> +
> /* From now till the next successful probe, ering is used to
> * track probe failures. Clear accumulated device error info.
> */
> diff --git a/drivers/ata/libata-sata.c b/drivers/ata/libata-sata.c
> index 498430db86f7..c8b119a06bb2 100644
> --- a/drivers/ata/libata-sata.c
> +++ b/drivers/ata/libata-sata.c
> @@ -1505,7 +1505,7 @@ int ata_eh_get_ncq_success_sense(struct ata_link *link)
> {
> struct ata_device *dev = link->device;
> struct ata_port *ap = dev->link->ap;
> - u8 *buf = ap->ncq_sense_buf;
> + u8 *buf = dev->cdl->ncq_sense_log_buf;
> struct ata_queued_cmd *qc;
> unsigned int err_mask, tag;
> u8 *sense, sk = 0, asc = 0, ascq = 0;
> diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
> index a3ffce4b218d..7fed924d6561 100644
> --- a/drivers/ata/libata-scsi.c
> +++ b/drivers/ata/libata-scsi.c
> @@ -2259,7 +2259,7 @@ static inline u16 ata_xlat_cdl_limit(u8 *buf)
> static unsigned int ata_msense_control_spgt2(struct ata_device *dev, u8 *buf,
> u8 spg)
> {
> - u8 *b, *cdl = dev->cdl, *desc;
> + u8 *b, *cdl = dev->cdl->desc_log_buf, *desc;
> u32 policy;
> int i;
>
> diff --git a/drivers/ata/libata.h b/drivers/ata/libata.h
> index 2a9d1bbf2482..0f4c6e26fe50 100644
> --- a/drivers/ata/libata.h
> +++ b/drivers/ata/libata.h
> @@ -89,6 +89,7 @@ extern int ata_cmd_ioctl(struct scsi_device *scsidev, void __user *arg);
> extern const char *sata_spd_string(unsigned int spd);
> extern unsigned int ata_read_log_page(struct ata_device *dev, u8 log,
> u8 page, void *buf, unsigned int sectors);
> +void ata_dev_cleanup_cdl_resources(struct ata_device *dev);
>
> #define to_ata_port(d) container_of(d, struct ata_port, tdev)
>
> diff --git a/include/linux/libata.h b/include/linux/libata.h
> index aac38dcd2230..9b4a6ff03235 100644
> --- a/include/linux/libata.h
> +++ b/include/linux/libata.h
> @@ -700,6 +700,21 @@ struct ata_cpr_log {
> struct ata_cpr cpr[] __counted_by(nr_cpr);
> };
>
> +struct ata_cdl {
> + /*
> + * Buffer to cache the CDL log page 18h (command duration descriptors)
> + * for SCSI-ATA translation.
> + */
> + u8 desc_log_buf[ATA_LOG_CDL_SIZE];
> +
> + /*
> + * Buffer to handle reading the sense data for successful NCQ Commands
> + * log page for commands using a CDL with one of the limits policy set
> + * to 0xD (successful completion with sense data available bit set).
> + */
> + u8 ncq_sense_log_buf[ATA_LOG_SENSE_NCQ_SIZE];
> +};
> +
> struct ata_device {
> struct ata_link *link;
> unsigned int devno; /* 0 or 1 */
> @@ -762,8 +777,8 @@ struct ata_device {
> /* Concurrent positioning ranges */
> struct ata_cpr_log *cpr_log;
>
> - /* Command Duration Limits log support */
> - u8 cdl[ATA_LOG_CDL_SIZE];
> + /* Command Duration Limits support */
> + struct ata_cdl *cdl;
>
> /* error history */
> int spdn_cnt;
> @@ -917,8 +932,6 @@ struct ata_port {
> #ifdef CONFIG_ATA_ACPI
> struct ata_acpi_gtm __acpi_init_gtm; /* use ata_acpi_init_gtm() */
> #endif
> - /* owned by EH */
> - u8 *ncq_sense_buf;
> };
>
> /* The following initializer overrides a method to NULL whether one of
> --
> 2.46.0
>
