RE: [Intel-wired-lan] [PATCH iwl v2] ice: acquire NVM lock around each flash read

[Loktionov, Aleksandr]

> -----Original Message-----
> From: Intel-wired-lan <intel-wired-lan-bounces@xxxxxxxxxx> On Behalf
> Of Robert Malz via Intel-wired-lan
> Sent: Friday, July 17, 2026 2:12 PM
> To: Nguyen, Anthony L <anthony.l.nguyen@xxxxxxxxx>; Kitszel,
> Przemyslaw <przemyslaw.kitszel@xxxxxxxxx>; Andrew Lunn
> <andrew+netdev@xxxxxxx>; David S. Miller <davem@xxxxxxxxxxxxx>; Eric
> Dumazet <edumazet@xxxxxxxxxx>; Jakub Kicinski <kuba@xxxxxxxxxx>; Paolo
> Abeni <pabeni@xxxxxxxxxx>; Lobakin, Aleksander
> <aleksander.lobakin@xxxxxxxxx>; Keller, Jacob E
> <jacob.e.keller@xxxxxxxxx>; Jesse Brandeburg <jbrandeb@xxxxxxxxxx>
> Cc: Robert Malz <robert.malz@xxxxxxxxxxxxx>; intel-wired-
> lan@xxxxxxxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx
> Subject: [Intel-wired-lan] [PATCH iwl v2] ice: acquire NVM lock around
> each flash read
> 
> FW caps the NVM read lock at a maximum of 3000ms regardless of the
> timeout requested via ice_acquire_nvm(). ice_read_flat_nvm() splits a
> read into multiple ice_aq_read_nvm() commands, one per 4KB sector, all
> issued under a single lock taken by the caller. Reading a large region
> can exceed 3000ms, so FW reclaims the lock mid-read and the remaining
> commands might fail.
> 
> Move the lock acquire/release into ice_read_flat_nvm() so it brackets
> each individual ice_aq_read_nvm() command, ensuring the lock is never
> held across more than one FW read.
> 
> ice_release_nvm() issues its own AQ command and overwrites
> hw->adminq.sq_last_status, which some callers inspect after a failed
> read.
> Add an optional read_aq_err output parameter to ice_read_flat_nvm() to
> capture the failing read's AQ error before the release; callers that
> need it (ice_discover_flash_size() and the ethtool/devlink log paths)
> use it instead of sq_last_status, others pass NULL.
> 
> Callers that previously took the lock around ice_read_flat_nvm(),
> ice_read_sr_word() or ice_read_flash_module() now call them without
> it.
> The now-redundant per-block locking in ice_devlink_nvm_snapshot() is
> dropped.
> 
> Fixes: e94509906d6b ("ice: create function to read a section of the
> NVM and Shadow RAM")
> Signed-off-by: Robert Malz <robert.malz@xxxxxxxxxxxxx>
> ---
> v2:
> - Replace the save/restore of sq_last_status across ice_release_nvm(),
>   which could race with a concurrent AdminQ command, with a new
> optional
>   read_aq_err output parameter.
> - Add missing "Return:" kdoc to ice_read_sr_word().
> ---
>  .../net/ethernet/intel/ice/devlink/devlink.c  | 32 ++------
> drivers/net/ethernet/intel/ice/ice_ethtool.c  | 16 +---
>  drivers/net/ethernet/intel/ice/ice_nvm.c      | 76 +++++++++++-------
> -
>  drivers/net/ethernet/intel/ice/ice_nvm.h      |  2 +-
>  4 files changed, 56 insertions(+), 70 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/ice/devlink/devlink.c
> b/drivers/net/ethernet/intel/ice/devlink/devlink.c
> index 22b7d8e6bd9e..5a1ab9654fb8 100644
> --- a/drivers/net/ethernet/intel/ice/devlink/devlink.c
> +++ b/drivers/net/ethernet/intel/ice/devlink/devlink.c
> @@ -1856,6 +1856,7 @@ static int ice_devlink_nvm_snapshot(struct
> devlink *devlink,  {
>  	struct ice_pf *pf = devlink_priv(devlink);
>  	struct device *dev = ice_pf_to_dev(pf);
> +	enum libie_aq_err read_aq_err = LIBIE_AQ_RC_OK;
>  	struct ice_hw *hw = &pf->hw;
>  	bool read_shadow_ram;
>  	u8 *nvm_data, *tmp, i;
> @@ -1891,26 +1892,16 @@ static int ice_devlink_nvm_snapshot(struct
> devlink *devlink,
>  	for (i = 0; i < num_blks; i++) {
>  		u32 read_sz = min_t(u32, ICE_DEVLINK_READ_BLK_SIZE,
> left);
> 

...

>  int
>  ice_get_pfa_module_tlv(struct ice_hw *hw, u16 *module_tlv, u16
> *module_tlv_len,
>  		       u16 module_type);
> --
> 2.34.1

Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@xxxxxxxxx>