[SRU,J,1/1] ice: acquire NVM lock around each flash read

diff --git a/drivers/net/ethernet/intel/ice/ice_devlink.c b/drivers/net/ethernet/intel/ice/ice_devlink.c
index 2ec5d5cb7280..c20bd31902ca 100644
--- a/drivers/net/ethernet/intel/ice/ice_devlink.c
+++ b/drivers/net/ethernet/intel/ice/ice_devlink.c
@@ -656,6 +656,7 @@  static int ice_devlink_nvm_snapshot(struct devlink *devlink,
 				    const struct devlink_region_ops *ops,
 				    struct netlink_ext_ack *extack, u8 **data)
 {
+	enum ice_aq_err read_aq_err = ICE_AQ_RC_OK;
 	struct ice_pf *pf = devlink_priv(devlink);
 	struct device *dev = ice_pf_to_dev(pf);
 	struct ice_hw *hw = &pf->hw;
@@ -668,27 +669,16 @@  static int ice_devlink_nvm_snapshot(struct devlink *devlink,
 	if (!nvm_data)
 		return -ENOMEM;
 
-	status = ice_acquire_nvm(hw, ICE_RES_READ);
-	if (status) {
-		dev_dbg(dev, "ice_acquire_nvm failed, err %d aq_err %d\n",
-			status, hw->adminq.sq_last_status);
-		NL_SET_ERR_MSG_MOD(extack, "Failed to acquire NVM semaphore");
-		vfree(nvm_data);
-		return -EIO;
-	}
-
-	status = ice_read_flat_nvm(hw, 0, &nvm_size, nvm_data, false);
+	status = ice_read_flat_nvm(hw, 0, &nvm_size, nvm_data, false,
+				   &read_aq_err);
 	if (status) {
 		dev_dbg(dev, "ice_read_flat_nvm failed after reading %u bytes, err %d aq_err %d\n",
-			nvm_size, status, hw->adminq.sq_last_status);
+			nvm_size, status, read_aq_err);
 		NL_SET_ERR_MSG_MOD(extack, "Failed to read NVM contents");
-		ice_release_nvm(hw);
 		vfree(nvm_data);
 		return -EIO;
 	}
 
-	ice_release_nvm(hw);
-
 	*data = nvm_data;
 
 	return 0;
diff --git a/drivers/net/ethernet/intel/ice/ice_ethtool.c b/drivers/net/ethernet/intel/ice/ice_ethtool.c
index 97a3def81d18..1086fca632e7 100644
--- a/drivers/net/ethernet/intel/ice/ice_ethtool.c
+++ b/drivers/net/ethernet/intel/ice/ice_ethtool.c
@@ -258,6 +258,7 @@  ice_get_eeprom(struct net_device *netdev, struct ethtool_eeprom *eeprom,
 	       u8 *bytes)
 {
 	struct ice_netdev_priv *np = netdev_priv(netdev);
+	enum ice_aq_err read_aq_err = ICE_AQ_RC_OK;
 	struct ice_vsi *vsi = np->vsi;
 	struct ice_pf *pf = vsi->back;
 	struct ice_hw *hw = &pf->hw;
@@ -276,28 +277,17 @@  ice_get_eeprom(struct net_device *netdev, struct ethtool_eeprom *eeprom,
 	if (!buf)
 		return -ENOMEM;
 
-	status = ice_acquire_nvm(hw, ICE_RES_READ);
-	if (status) {
-		dev_err(dev, "ice_acquire_nvm failed, err %s aq_err %s\n",
-			ice_stat_str(status),
-			ice_aq_str(hw->adminq.sq_last_status));
-		ret = -EIO;
-		goto out;
-	}
-
 	status = ice_read_flat_nvm(hw, eeprom->offset, &eeprom->len, buf,
-				   false);
+				   false, &read_aq_err);
 	if (status) {
 		dev_err(dev, "ice_read_flat_nvm failed, err %s aq_err %s\n",
 			ice_stat_str(status),
-			ice_aq_str(hw->adminq.sq_last_status));
+			ice_aq_str(read_aq_err));
 		ret = -EIO;
-		goto release;
+		goto out;
 	}
 
 	memcpy(bytes, buf, eeprom->len);
-release:
-	ice_release_nvm(hw);
 out:
 	kfree(buf);
 	return ret;
diff --git a/drivers/net/ethernet/intel/ice/ice_nvm.c b/drivers/net/ethernet/intel/ice/ice_nvm.c
index fee37a5844cf..5e78155b302a 100644
--- a/drivers/net/ethernet/intel/ice/ice_nvm.c
+++ b/drivers/net/ethernet/intel/ice/ice_nvm.c
@@ -52,17 +52,27 @@  ice_aq_read_nvm(struct ice_hw *hw, u16 module_typeid, u32 offset, u16 length,
  * @length: (in) number of bytes to read; (out) number of bytes actually read
  * @data: buffer to return data in (sized to fit the specified length)
  * @read_shadow_ram: if true, read from shadow RAM instead of NVM
+ * @read_aq_err: if non-NULL, receives the AQ error status of the failing read
  *
  * Reads a portion of the NVM, as a flat memory space. This function correctly
  * breaks read requests across Shadow RAM sectors and ensures that no single
  * read request exceeds the maximum 4KB read for a single AdminQ command.
  *
+ * FW caps the read lock at a maximum of 3000ms, so a read spanning multiple
+ * 4KB sectors cannot be done under a single lock without FW reclaiming it
+ * mid-read. The NVM lock is therefore acquired and released around each AQ
+ * read, so this function must be called without the lock held.
+ *
+ * Since ice_release_nvm() issues an AQ command that overwrites
+ * hw->adminq.sq_last_status, callers that need the failing read's AQ error
+ * must use @read_aq_err rather than inspecting sq_last_status afterwards.
+ *
  * Returns a status code on failure. Note that the data pointer may be
  * partially updated if some reads succeed before a failure.
  */
 enum ice_status
 ice_read_flat_nvm(struct ice_hw *hw, u32 offset, u32 *length, u8 *data,
-		  bool read_shadow_ram)
+		  bool read_shadow_ram, enum ice_aq_err *read_aq_err)
 {
 	enum ice_status status;
 	u32 inlen = *length;
@@ -91,12 +101,30 @@  ice_read_flat_nvm(struct ice_hw *hw, u32 offset, u32 *length, u8 *data,
 
 		last_cmd = !(bytes_read + read_size < inlen);
 
+		status = ice_acquire_nvm(hw, ICE_RES_READ);
+		if (status) {
+			ice_debug(hw, ICE_DBG_NVM, "Failed to acquire NVM lock, err %d aq_err %d\n",
+				  status, hw->adminq.sq_last_status);
+			break;
+		}
+
 		status = ice_aq_read_nvm(hw, ICE_AQC_NVM_START_POINT,
 					 offset, read_size,
 					 data + bytes_read, last_cmd,
 					 read_shadow_ram, NULL);
-		if (status)
+		if (status) {
+			/* Capture the read's AQ error before ice_release_nvm()
+			 * issues its own AQ command and overwrites
+			 * sq_last_status.
+			 */
+			if (read_aq_err)
+				*read_aq_err = hw->adminq.sq_last_status;
+
+			ice_release_nvm(hw);
 			break;
+		}
+
+		ice_release_nvm(hw);
 
 		bytes_read += read_size;
 		offset += read_size;
@@ -177,15 +205,19 @@  ice_aq_erase_nvm(struct ice_hw *hw, u16 module_typeid, struct ice_sq_cd *cd)
 }
 
 /**
- * ice_read_sr_word_aq - Reads Shadow RAM via AQ
+ * ice_read_sr_word - Reads Shadow RAM word
  * @hw: pointer to the HW structure
  * @offset: offset of the Shadow RAM word to read (0x000000 - 0x001FFF)
  * @data: word read from the Shadow RAM
  *
  * Reads one 16 bit word from the Shadow RAM using ice_read_flat_nvm.
+ *
+ * The NVM lock is acquired and released internally by ice_read_flat_nvm()
+ * around the FW read, so this function must be called without the lock held.
+ *
+ * Return: zero on success, or a negative error code on failure.
  */
-static enum ice_status
-ice_read_sr_word_aq(struct ice_hw *hw, u16 offset, u16 *data)
+enum ice_status ice_read_sr_word(struct ice_hw *hw, u16 offset, u16 *data)
 {
 	u32 bytes = sizeof(u16);
 	enum ice_status status;
@@ -195,7 +227,7 @@  ice_read_sr_word_aq(struct ice_hw *hw, u16 offset, u16 *data)
 	 * Shadow RAM sector restrictions necessary when reading from the NVM.
 	 */
 	status = ice_read_flat_nvm(hw, offset * sizeof(u16), &bytes,
-				   (__force u8 *)&data_local, true);
+				   (__force u8 *)&data_local, true, NULL);
 	if (status)
 		return status;
 
@@ -332,13 +364,8 @@  ice_read_flash_module(struct ice_hw *hw, enum ice_bank_select bank, u16 module,
 		return ICE_ERR_PARAM;
 	}
 
-	status = ice_acquire_nvm(hw, ICE_RES_READ);
-	if (status)
-		return status;
-
-	status = ice_read_flat_nvm(hw, start + offset, &length, data, false);
-
-	ice_release_nvm(hw);
+	status = ice_read_flat_nvm(hw, start + offset, &length, data, false,
+				   NULL);
 
 	return status;
 }
@@ -406,27 +433,6 @@  ice_read_netlist_module(struct ice_hw *hw, enum ice_bank_select bank, u32 offset
 	return status;
 }
 
-/**
- * ice_read_sr_word - Reads Shadow RAM word and acquire NVM if necessary
- * @hw: pointer to the HW structure
- * @offset: offset of the Shadow RAM word to read (0x000000 - 0x001FFF)
- * @data: word read from the Shadow RAM
- *
- * Reads one 16 bit word from the Shadow RAM using the ice_read_sr_word_aq.
- */
-enum ice_status ice_read_sr_word(struct ice_hw *hw, u16 offset, u16 *data)
-{
-	enum ice_status status;
-
-	status = ice_acquire_nvm(hw, ICE_RES_READ);
-	if (!status) {
-		status = ice_read_sr_word_aq(hw, offset, data);
-		ice_release_nvm(hw);
-	}
-
-	return status;
-}
-
 /**
  * ice_get_pfa_module_tlv - Reads sub module TLV from NVM PFA
  * @hw: pointer to hardware structure
@@ -807,20 +813,18 @@  enum ice_status ice_get_inactive_netlist_ver(struct ice_hw *hw, struct ice_netli
 static enum ice_status ice_discover_flash_size(struct ice_hw *hw)
 {
 	u32 min_size = 0, max_size = ICE_AQC_NVM_MAX_OFFSET + 1;
-	enum ice_status status;
-
-	status = ice_acquire_nvm(hw, ICE_RES_READ);
-	if (status)
-		return status;
+	enum ice_status status = 0;
 
 	while ((max_size - min_size) > 1) {
+		enum ice_aq_err read_aq_err = ICE_AQ_RC_OK;
 		u32 offset = (max_size + min_size) / 2;
 		u32 len = 1;
 		u8 data;
 
-		status = ice_read_flat_nvm(hw, offset, &len, &data, false);
+		status = ice_read_flat_nvm(hw, offset, &len, &data, false,
+					   &read_aq_err);
 		if (status == ICE_ERR_AQ_ERROR &&
-		    hw->adminq.sq_last_status == ICE_AQ_RC_EINVAL) {
+		    read_aq_err == ICE_AQ_RC_EINVAL) {
 			ice_debug(hw, ICE_DBG_NVM, "%s: New upper bound of %u bytes\n",
 				  __func__, offset);
 			status = 0;
@@ -831,7 +835,7 @@  static enum ice_status ice_discover_flash_size(struct ice_hw *hw)
 			min_size = offset;
 		} else {
 			/* an unexpected error occurred */
-			goto err_read_flat_nvm;
+			return status;
 		}
 	}
 
@@ -839,9 +843,6 @@  static enum ice_status ice_discover_flash_size(struct ice_hw *hw)
 
 	hw->flash.flash_size = max_size;
 
-err_read_flat_nvm:
-	ice_release_nvm(hw);
-
 	return status;
 }
 
diff --git a/drivers/net/ethernet/intel/ice/ice_nvm.h b/drivers/net/ethernet/intel/ice/ice_nvm.h
index c6f05f43d593..371da1b69022 100644
--- a/drivers/net/ethernet/intel/ice/ice_nvm.h
+++ b/drivers/net/ethernet/intel/ice/ice_nvm.h
@@ -17,7 +17,7 @@  ice_acquire_nvm(struct ice_hw *hw, enum ice_aq_res_access_type access);
 void ice_release_nvm(struct ice_hw *hw);
 enum ice_status
 ice_read_flat_nvm(struct ice_hw *hw, u32 offset, u32 *length, u8 *data,
-		  bool read_shadow_ram);
+		  bool read_shadow_ram, enum ice_aq_err *read_aq_err);
 enum ice_status
 ice_get_pfa_module_tlv(struct ice_hw *hw, u16 *module_tlv, u16 *module_tlv_len,
 		       u16 module_type);