On Fri, Sep 06, 2024 at 10:58:47AM +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 freeing 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_dev_free_resources()
> to free the ata_cdl structure when a device is being disabled by EH.
>
> 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>
> ---
> drivers/ata/libata-core.c | 60 +++++++++++++++++++++++----------------
> drivers/ata/libata-sata.c | 2 +-
> drivers/ata/libata-scsi.c | 2 +-
> drivers/ata/libata.h | 1 +
> include/linux/libata.h | 21 +++++++++++---
> 5 files changed, 56 insertions(+), 30 deletions(-)
>
> diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
> index bfd452b0d46d..bd2f8e442b14 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(*cdl), GFP_KERNEL);
> + 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;
Usually when a function return error, you expect it to have freed the
resources that it might have allocated, so perhaps free and set
dev->cdl to NULL here.
> + }
> +
> + 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);
Considering that you now do ata_dev_init_cdl_resources() at the end,
if you implement my suggestion above, we can remove the call to
ata_dev_cleanup_cdl_resources() here, since we will only jump here
if the ata_dev_init_cdl_resources() call failed.
Either way:
Reviewed-by: Niklas Cassel <cassel@xxxxxxxxxx>
> }
>
> static int ata_dev_config_lba(struct ata_device *dev)
