[PATCH v2 0/4] ufs: core: Always read the descriptors with max length

[PATCH v2 0/4] ufs: core: Always read the descriptors with max length

[Arthur Simchaev]

v2--v3:
  Based on Bean's comments:
  1)Use kzalloc instead of kmalloc in ufshcd_set_active_icc_lvl - patch 2/4
  2)Delete  UFS_RPMB_UNIT definition - patch 2/4
  3)Delete len description - patch 3/4

v1--v2:
  Fix argument warning in ufshpb.c

Read any descriptor with a maximum size of QUERY_DESC_MAX_SIZE.
According to the spec the device rerurns the actual size.
Thus can improve code readability and save CPU cycles.
While at it, cleanup few leftovers around the descriptor size parameter.

Suggested-by: Bean Huo <beanhuo@micron.com>

Arthur Simchaev (4):
  ufs:core: Remove redundant wb check
  ufs:core: Remove redundant desc_size variable from hba
  ufs: core: Remove len parameter from ufshcd_set_active_icc_lvl
  ufs: core: Remove ufshcd_map_desc_id_to_length function

 drivers/ufs/core/ufs_bsg.c     |   7 +--
 drivers/ufs/core/ufshcd-priv.h |   3 --
 drivers/ufs/core/ufshcd.c      | 100 ++++++++++-------------------------------
 drivers/ufs/core/ufshpb.c      |   5 +--
 include/ufs/ufshcd.h           |   1 -
 5 files changed, 26 insertions(+), 90 deletions(-)

-- 
2.7.4

[PATCH v3 1/4] ufs: core: Remove redundant wb check

[Arthur Simchaev]

We used to use the extended-feature field in the device descriptor,
as an indication that the device supports ufs2.2 or later.
Remove that as this check is specifically done few lines above.

Signed-off-by: Arthur Simchaev <Arthur.Simchaev@wdc.com>
---
 drivers/ufs/core/ufshcd.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index 768cb49..301fda0 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -7584,10 +7584,6 @@ static void ufshcd_wb_probe(struct ufs_hba *hba, const u8 *desc_buf)
 	     (hba->dev_quirks & UFS_DEVICE_QUIRK_SUPPORT_EXTENDED_FEATURES)))
 		goto wb_disabled;
 
-	if (hba->desc_size[QUERY_DESC_IDN_DEVICE] <
-	    DEVICE_DESC_PARAM_EXT_UFS_FEATURE_SUP + 4)
-		goto wb_disabled;
-
 	ext_ufs_feature = get_unaligned_be32(desc_buf +
 					DEVICE_DESC_PARAM_EXT_UFS_FEATURE_SUP);
 
-- 
2.7.4

[PATCH v3 2/4] ufs: core: Remove redundant desc_size variable from hba

[Arthur Simchaev]

Always read the descriptor with QUERY_DESC_MAX_SIZE.
According to the spec, the device returns the actual size

Signed-off-by: Arthur Simchaev <Arthur.Simchaev@wdc.com>
---
 drivers/ufs/core/ufshcd.c | 51 ++++++++++++-----------------------------------
 include/ufs/ufs.h         |  1 -
 include/ufs/ufshcd.h      |  1 -
 3 files changed, 13 insertions(+), 40 deletions(-)

diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index 301fda0..7456aa2 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -3377,28 +3377,11 @@ int ufshcd_query_descriptor_retry(struct ufs_hba *hba,
 void ufshcd_map_desc_id_to_length(struct ufs_hba *hba, enum desc_idn desc_id,
 				  int *desc_len)
 {
-	if (desc_id >= QUERY_DESC_IDN_MAX || desc_id == QUERY_DESC_IDN_RFU_0 ||
-	    desc_id == QUERY_DESC_IDN_RFU_1)
-		*desc_len = 0;
-	else
-		*desc_len = hba->desc_size[desc_id];
+	/*Always returns QUERY_DESC_MAX_SIZE*/
+	*desc_len = QUERY_DESC_MAX_SIZE;
 }
 EXPORT_SYMBOL(ufshcd_map_desc_id_to_length);
 
-static void ufshcd_update_desc_length(struct ufs_hba *hba,
-				      enum desc_idn desc_id, int desc_index,
-				      unsigned char desc_len)
-{
-	if (hba->desc_size[desc_id] == QUERY_DESC_MAX_SIZE &&
-	    desc_id != QUERY_DESC_IDN_STRING && desc_index != UFS_RPMB_UNIT)
-		/* For UFS 3.1, the normal unit descriptor is 10 bytes larger
-		 * than the RPMB unit, however, both descriptors share the same
-		 * desc_idn, to cover both unit descriptors with one length, we
-		 * choose the normal unit descriptor length by desc_index.
-		 */
-		hba->desc_size[desc_id] = desc_len;
-}
-
 /**
  * ufshcd_read_desc_param - read the specified descriptor parameter
  * @hba: Pointer to adapter instance
@@ -3470,7 +3453,6 @@ int ufshcd_read_desc_param(struct ufs_hba *hba,
 
 	/* Update descriptor length */
 	buff_len = desc_buf[QUERY_DESC_LENGTH_OFFSET];
-	ufshcd_update_desc_length(hba, desc_id, desc_index, buff_len);
 
 	if (is_kmalloc) {
 		/* Make sure we don't copy more data than available */
@@ -4909,7 +4891,7 @@ static void ufshcd_setup_links(struct ufs_hba *hba, struct scsi_device *sdev)
  */
 static void ufshcd_lu_init(struct ufs_hba *hba, struct scsi_device *sdev)
 {
-	int len = hba->desc_size[QUERY_DESC_IDN_UNIT];
+	int len = QUERY_DESC_MAX_SIZE;
 	u8 lun = ufshcd_scsi_to_upiu_lun(sdev->lun);
 	u8 lun_qdepth = hba->nutrs;
 	u8 *desc_buf;
@@ -7456,25 +7438,24 @@ static u32 ufshcd_find_max_sup_active_icc_level(struct ufs_hba *hba,
 static void ufshcd_set_active_icc_lvl(struct ufs_hba *hba)
 {
 	int ret;
-	int buff_len = hba->desc_size[QUERY_DESC_IDN_POWER];
 	u8 *desc_buf;
 	u32 icc_level;
 
-	desc_buf = kmalloc(buff_len, GFP_KERNEL);
+	desc_buf = kzalloc(QUERY_DESC_MAX_SIZE, GFP_KERNEL);
 	if (!desc_buf)
 		return;
 
 	ret = ufshcd_read_desc_param(hba, QUERY_DESC_IDN_POWER, 0, 0,
-				     desc_buf, buff_len);
+				     desc_buf, QUERY_DESC_MAX_SIZE);
 	if (ret) {
 		dev_err(hba->dev,
-			"%s: Failed reading power descriptor.len = %d ret = %d",
-			__func__, buff_len, ret);
+			"%s: Failed reading power descriptor ret = %d",
+			__func__, ret);
 		goto out;
 	}
 
 	icc_level = ufshcd_find_max_sup_active_icc_level(hba, desc_buf,
-							 buff_len);
+							 QUERY_DESC_MAX_SIZE);
 	dev_dbg(hba->dev, "%s: setting icc_level 0x%x", __func__, icc_level);
 
 	ret = ufshcd_query_attr_retry(hba, UPIU_QUERY_OPCODE_WRITE_ATTR,
@@ -7698,7 +7679,7 @@ static int ufs_get_device_desc(struct ufs_hba *hba)
 	}
 
 	err = ufshcd_read_desc_param(hba, QUERY_DESC_IDN_DEVICE, 0, 0, desc_buf,
-				     hba->desc_size[QUERY_DESC_IDN_DEVICE]);
+				     QUERY_DESC_MAX_SIZE);
 	if (err) {
 		dev_err(hba->dev, "%s: Failed reading Device Desc. err = %d\n",
 			__func__, err);
@@ -7945,18 +7926,16 @@ static void ufshcd_clear_dbg_ufs_stats(struct ufs_hba *hba)
 static int ufshcd_device_geo_params_init(struct ufs_hba *hba)
 {
 	int err;
-	size_t buff_len;
 	u8 *desc_buf;
 
-	buff_len = hba->desc_size[QUERY_DESC_IDN_GEOMETRY];
-	desc_buf = kmalloc(buff_len, GFP_KERNEL);
+	desc_buf = kmalloc(QUERY_DESC_MAX_SIZE, GFP_KERNEL);
 	if (!desc_buf) {
 		err = -ENOMEM;
 		goto out;
 	}
 
 	err = ufshcd_read_desc_param(hba, QUERY_DESC_IDN_GEOMETRY, 0, 0,
-				     desc_buf, buff_len);
+				     desc_buf, QUERY_DESC_MAX_SIZE);
 	if (err) {
 		dev_err(hba->dev, "%s: Failed reading Geometry Desc. err = %d\n",
 				__func__, err);
@@ -7968,7 +7947,7 @@ static int ufshcd_device_geo_params_init(struct ufs_hba *hba)
 	else if (desc_buf[GEOMETRY_DESC_PARAM_MAX_NUM_LUN] == 0)
 		hba->dev_info.max_lu_supported = 8;
 
-	if (hba->desc_size[QUERY_DESC_IDN_GEOMETRY] >=
+	if (desc_buf[QUERY_DESC_LENGTH_OFFSET] >=
 		GEOMETRY_DESC_PARAM_HPB_MAX_ACTIVE_REGS)
 		ufshpb_get_geo_info(hba, desc_buf);
 
@@ -8053,11 +8032,7 @@ static int ufshcd_set_dev_ref_clk(struct ufs_hba *hba)
 static int ufshcd_device_params_init(struct ufs_hba *hba)
 {
 	bool flag;
-	int ret, i;
-
-	 /* Init device descriptor sizes */
-	for (i = 0; i < QUERY_DESC_IDN_MAX; i++)
-		hba->desc_size[i] = QUERY_DESC_MAX_SIZE;
+	int ret;
 
 	/* Init UFS geometry descriptor related parameters */
 	ret = ufshcd_device_geo_params_init(hba);
diff --git a/include/ufs/ufs.h b/include/ufs/ufs.h
index 1bba3fe..2fc7107 100644
--- a/include/ufs/ufs.h
+++ b/include/ufs/ufs.h
@@ -38,7 +38,6 @@
 #define UFS_UPIU_MAX_UNIT_NUM_ID	0x7F
 #define UFS_MAX_LUNS		(SCSI_W_LUN_BASE + UFS_UPIU_MAX_UNIT_NUM_ID)
 #define UFS_UPIU_WLUN_ID	(1 << 7)
-#define UFS_RPMB_UNIT		0xC4
 
 /* WriteBooster buffer is available only for the logical unit from 0 to 7 */
 #define UFS_UPIU_MAX_WB_LUN_ID	8
diff --git a/include/ufs/ufshcd.h b/include/ufs/ufshcd.h
index 5cf81df..7df2ce1 100644
--- a/include/ufs/ufshcd.h
+++ b/include/ufs/ufshcd.h
@@ -952,7 +952,6 @@ struct ufs_hba {
 	bool is_urgent_bkops_lvl_checked;
 
 	struct rw_semaphore clk_scaling_lock;
-	unsigned char desc_size[QUERY_DESC_IDN_MAX];
 	atomic_t scsi_block_reqs_cnt;
 
 	struct device		bsg_dev;
-- 
2.7.4

[PATCH v3 3/4] ufs: core: Remove len parameter from ufshcd_set_active_icc_lvl

[Arthur Simchaev]

len argument is not used anymore in ufshcd_set_active_icc_lvl function.

Signed-off-by: Arthur Simchaev <Arthur.Simchaev@wdc.com>
---
 drivers/ufs/core/ufshcd.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index 7456aa2..604348f 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -7391,12 +7391,11 @@ static u32 ufshcd_get_max_icc_level(int sup_curr_uA, u32 start_scan,
  * In case regulators are not initialized we'll return 0
  * @hba: per-adapter instance
  * @desc_buf: power descriptor buffer to extract ICC levels from.
- * @len: length of desc_buff
  *
  * Returns calculated ICC level
  */
 static u32 ufshcd_find_max_sup_active_icc_level(struct ufs_hba *hba,
-						const u8 *desc_buf, int len)
+						const u8 *desc_buf)
 {
 	u32 icc_level = 0;
 
@@ -7454,8 +7453,7 @@ static void ufshcd_set_active_icc_lvl(struct ufs_hba *hba)
 		goto out;
 	}
 
-	icc_level = ufshcd_find_max_sup_active_icc_level(hba, desc_buf,
-							 QUERY_DESC_MAX_SIZE);
+	icc_level = ufshcd_find_max_sup_active_icc_level(hba, desc_buf);
 	dev_dbg(hba->dev, "%s: setting icc_level 0x%x", __func__, icc_level);
 
 	ret = ufshcd_query_attr_retry(hba, UPIU_QUERY_OPCODE_WRITE_ATTR,
-- 
2.7.4

[PATCH v3 4/4] ufs: core: Remove ufshcd_map_desc_id_to_length function

[Arthur Simchaev]

There shouldn't be any restriction of the descriptor size
(not the descriptor id for that matter) up to QUERY_DESC_MAX_SIZE.
According to the spec, the caller can use any descriptor size,
and it is up to the device to return the actual size.
Therefore there shouldn't be any sizes hardcoded in the kernel,
nor any need to cache it, hence ufshcd_map_desc_id_to_length function is redundant.
always read the descriptors with QUERY_DESC_MAX_SIZE size.

Suggested-by: Bean Huo <beanhuo@micron.com>

Signed-off-by: Arthur Simchaev <Arthur.Simchaev@wdc.com>
---
 drivers/ufs/core/ufs_bsg.c     |  7 +------
 drivers/ufs/core/ufshcd-priv.h |  3 ---
 drivers/ufs/core/ufshcd.c      | 46 +++++++++++-------------------------------
 drivers/ufs/core/ufshpb.c      |  4 +---
 4 files changed, 14 insertions(+), 46 deletions(-)

diff --git a/drivers/ufs/core/ufs_bsg.c b/drivers/ufs/core/ufs_bsg.c
index b99e3f3..dc441ac 100644
--- a/drivers/ufs/core/ufs_bsg.c
+++ b/drivers/ufs/core/ufs_bsg.c
@@ -16,16 +16,11 @@ static int ufs_bsg_get_query_desc_size(struct ufs_hba *hba, int *desc_len,
 				       struct utp_upiu_query *qr)
 {
 	int desc_size = be16_to_cpu(qr->length);
-	int desc_id = qr->idn;
 
 	if (desc_size <= 0)
 		return -EINVAL;
 
-	ufshcd_map_desc_id_to_length(hba, desc_id, desc_len);
-	if (!*desc_len)
-		return -EINVAL;
-
-	*desc_len = min_t(int, *desc_len, desc_size);
+	*desc_len = min_t(int, QUERY_DESC_MAX_SIZE, desc_size);
 
 	return 0;
 }
diff --git a/drivers/ufs/core/ufshcd-priv.h b/drivers/ufs/core/ufshcd-priv.h
index a9e8e1f..c52e2f3 100644
--- a/drivers/ufs/core/ufshcd-priv.h
+++ b/drivers/ufs/core/ufshcd-priv.h
@@ -70,9 +70,6 @@ int ufshcd_read_string_desc(struct ufs_hba *hba, u8 desc_index,
 int ufshcd_hold(struct ufs_hba *hba, bool async);
 void ufshcd_release(struct ufs_hba *hba);
 
-void ufshcd_map_desc_id_to_length(struct ufs_hba *hba, enum desc_idn desc_id,
-				  int *desc_length);
-
 int ufshcd_send_uic_cmd(struct ufs_hba *hba, struct uic_command *uic_cmd);
 
 int ufshcd_exec_raw_upiu_cmd(struct ufs_hba *hba,
diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index 604348f..7990922 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -3369,20 +3369,6 @@ int ufshcd_query_descriptor_retry(struct ufs_hba *hba,
 }
 
 /**
- * ufshcd_map_desc_id_to_length - map descriptor IDN to its length
- * @hba: Pointer to adapter instance
- * @desc_id: descriptor idn value
- * @desc_len: mapped desc length (out)
- */
-void ufshcd_map_desc_id_to_length(struct ufs_hba *hba, enum desc_idn desc_id,
-				  int *desc_len)
-{
-	/*Always returns QUERY_DESC_MAX_SIZE*/
-	*desc_len = QUERY_DESC_MAX_SIZE;
-}
-EXPORT_SYMBOL(ufshcd_map_desc_id_to_length);
-
-/**
  * ufshcd_read_desc_param - read the specified descriptor parameter
  * @hba: Pointer to adapter instance
  * @desc_id: descriptor idn value
@@ -3402,26 +3388,13 @@ int ufshcd_read_desc_param(struct ufs_hba *hba,
 {
 	int ret;
 	u8 *desc_buf;
-	int buff_len;
+	int buff_len = QUERY_DESC_MAX_SIZE;
 	bool is_kmalloc = true;
 
 	/* Safety check */
 	if (desc_id >= QUERY_DESC_IDN_MAX || !param_size)
 		return -EINVAL;
 
-	/* Get the length of descriptor */
-	ufshcd_map_desc_id_to_length(hba, desc_id, &buff_len);
-	if (!buff_len) {
-		dev_err(hba->dev, "%s: Failed to get desc length\n", __func__);
-		return -EINVAL;
-	}
-
-	if (param_offset >= buff_len) {
-		dev_err(hba->dev, "%s: Invalid offset 0x%x in descriptor IDN 0x%x, length 0x%x\n",
-			__func__, param_offset, desc_id, buff_len);
-		return -EINVAL;
-	}
-
 	/* Check whether we need temp memory */
 	if (param_offset != 0 || param_size < buff_len) {
 		desc_buf = kzalloc(buff_len, GFP_KERNEL);
@@ -3434,15 +3407,23 @@ int ufshcd_read_desc_param(struct ufs_hba *hba,
 
 	/* Request for full descriptor */
 	ret = ufshcd_query_descriptor_retry(hba, UPIU_QUERY_OPCODE_READ_DESC,
-					desc_id, desc_index, 0,
-					desc_buf, &buff_len);
-
+					    desc_id, desc_index, 0,
+					    desc_buf, &buff_len);
 	if (ret) {
 		dev_err(hba->dev, "%s: Failed reading descriptor. desc_id %d, desc_index %d, param_offset %d, ret %d\n",
 			__func__, desc_id, desc_index, param_offset, ret);
 		goto out;
 	}
 
+	/* Update descriptor length */
+	buff_len = desc_buf[QUERY_DESC_LENGTH_OFFSET];
+
+	if (param_offset >= buff_len) {
+		dev_err(hba->dev, "%s: Invalid offset 0x%x in descriptor IDN 0x%x, length 0x%x\n",
+			__func__, param_offset, desc_id, buff_len);
+		return -EINVAL;
+	}
+
 	/* Sanity check */
 	if (desc_buf[QUERY_DESC_DESC_TYPE_OFFSET] != desc_id) {
 		dev_err(hba->dev, "%s: invalid desc_id %d in descriptor header\n",
@@ -3451,9 +3432,6 @@ int ufshcd_read_desc_param(struct ufs_hba *hba,
 		goto out;
 	}
 
-	/* Update descriptor length */
-	buff_len = desc_buf[QUERY_DESC_LENGTH_OFFSET];
-
 	if (is_kmalloc) {
 		/* Make sure we don't copy more data than available */
 		if (param_offset >= buff_len)
diff --git a/drivers/ufs/core/ufshpb.c b/drivers/ufs/core/ufshpb.c
index 3d69a81c..11f8aa6 100644
--- a/drivers/ufs/core/ufshpb.c
+++ b/drivers/ufs/core/ufshpb.c
@@ -2382,12 +2382,10 @@ static int ufshpb_get_lu_info(struct ufs_hba *hba, int lun,
 {
 	u16 max_active_rgns;
 	u8 lu_enable;
-	int size;
+	int size = QUERY_DESC_MAX_SIZE;
 	int ret;
 	char desc_buf[QUERY_DESC_MAX_SIZE];
 
-	ufshcd_map_desc_id_to_length(hba, QUERY_DESC_IDN_UNIT, &size);
-
 	ufshcd_rpm_get_sync(hba);
 	ret = ufshcd_query_descriptor_retry(hba, UPIU_QUERY_OPCODE_READ_DESC,
 					    QUERY_DESC_IDN_UNIT, lun, 0,
-- 
2.7.4

Re: [PATCH v3 1/4] ufs: core: Remove redundant wb check

[Bean Huo]

On Mon, 2022-11-21 at 17:46 +0200, Arthur Simchaev wrote:
> We used to use the extended-feature field in the device descriptor,
> 
> as an indication that the device supports ufs2.2 or later.
> 
> Remove that as this check is specifically done few lines above.
> 
> 
> 
> Signed-off-by: Arthur Simchaev <Arthur.Simchaev@wdc.com>

Reviewed-by: Bean Huo <beanhuo@micron.com>

Re: [PATCH v3 2/4] ufs: core: Remove redundant desc_size variable from hba

[Bean Huo]

On Mon, 2022-11-21 at 17:46 +0200, Arthur Simchaev wrote:
> @ -7945,18 +7926,16 @@ static void ufshcd_clear_dbg_ufs_stats(struct
> ufs_hba *hba)
> 
>  static int ufshcd_device_geo_params_init(struct ufs_hba *hba)
> 
>  {
> 
>         int err;
> 
> -       size_t buff_len;
> 
>         u8 *desc_buf;
> 
>  
> 
> -       buff_len = hba->desc_size[QUERY_DESC_IDN_GEOMETRY];
> 
> -       desc_buf = kmalloc(buff_len, GFP_KERNEL);
> 
> +       desc_buf = kmalloc(QUERY_DESC_MAX_SIZE, GFP_KERNEL);
here also should be kzalloc?

Reviewed-by: Bean Huo <beanhuo@micron.com>

Re: [PATCH v3 3/4] ufs: core: Remove len parameter from ufshcd_set_active_icc_lvl

[Bean Huo]

On Mon, 2022-11-21 at 17:46 +0200, Arthur Simchaev wrote:
> len argument is not used anymore in ufshcd_set_active_icc_lvl
> function.
> 
> Signed-off-by: Arthur Simchaev <Arthur.Simchaev@wdc.com>
> ---
>  drivers/ufs/core/ufshcd.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
> index 7456aa2..604348f 100644
> --- a/drivers/ufs/core/ufshcd.c
> +++ b/drivers/ufs/core/ufshcd.c
> @@ -7391,12 +7391,11 @@ static u32 ufshcd_get_max_icc_level(int
> sup_curr_uA, u32 start_scan,
>   * In case regulators are not initialized we'll return 0
>   * @hba: per-adapter instance
>   * @desc_buf: power descriptor buffer to extract ICC levels from.
> - * @len: length of desc_buff
>   *
>   * Returns calculated ICC level
>   */
>  static u32 ufshcd_find_max_sup_active_icc_level(struct ufs_hba *hba,
> -						const u8 *desc_buf, int
> len)
> +						const u8 *desc_buf)


The Linux kernel already deprecates the 80 character per line coding
style, so you could keep one line here after removing len.


Reviewed-by: Bean Huo <beanhuo@micron.com>

Re: [PATCH v3 4/4] ufs: core: Remove ufshcd_map_desc_id_to_length function

[Bean Huo]

On Mon, 2022-11-21 at 17:46 +0200, Arthur Simchaev wrote:
............
> -	if (param_offset >= buff_len) {
> -		dev_err(hba->dev, "%s: Invalid offset 0x%x in
> descriptor IDN 0x%x, length 0x%x\n",
> -			__func__, param_offset, desc_id, buff_len);
> -		return -EINVAL;
> -	}
> -
>  	/* Check whether we need temp memory */
>  	if (param_offset != 0 || param_size < buff_len) {
>  		desc_buf = kzalloc(buff_len, GFP_KERNEL);
> @@ -3434,15 +3407,23 @@ int ufshcd_read_desc_param(struct ufs_hba
> *hba,
>  
>  	/* Request for full descriptor */
>  	ret = ufshcd_query_descriptor_retry(hba,
> UPIU_QUERY_OPCODE_READ_DESC,
> -					desc_id, desc_index, 0,
> -					desc_buf, &buff_len);
> -
> +					    desc_id, desc_index, 0,
> +					    desc_buf, &buff_len);
>  	if (ret) {
>  		dev_err(hba->dev, "%s: Failed reading descriptor.
> desc_id %d, desc_index %d, param_offset %d, ret %d\n",
>  			__func__, desc_id, desc_index, param_offset,
> ret);
>  		goto out;
>  	}
>  
> +	/* Update descriptor length */
> +	buff_len = desc_buf[QUERY_DESC_LENGTH_OFFSET];
> +
> +	if (param_offset >= buff_len) {
> +		dev_err(hba->dev, "%s: Invalid offset 0x%x in
> descriptor IDN 0x%x, length 0x%x\n",
> +			__func__, param_offset, desc_id, buff_len);
> +		return -EINVAL;
> +	}
> +

a little bit concerned here, but understood your point that you want to
anyway read descriptor, then check if param_offset is a valid input. I
think, there is no problem. 

All in all, this series is a very nice cleanup, we removed all
unnecessary if-state, and complicated rules, making code more readable
than before.

Reviewed-by: Bean Huo <beanhuo@micron.com>


Thanks,
Bean

[PATCH v2 0/4] ufs: core: Always read the descriptors with max length

[Arthur Simchaev]

v1--v2:
  Fix argument warning in ufshpb.c

Read any descriptor with a maximum size of QUERY_DESC_MAX_SIZE.
According to the spec the device rerurns the actual size.
Thus can improve code readability and save CPU cycles.
While at it, cleanup few leftovers around the descriptor size parameter.

Suggested-by: Bean Huo <beanhuo@micron.com>

Arthur Simchaev (4):
  ufs:core: Remove redundant wb check
  ufs:core: Remove redundant desc_size variable from hba
  ufs: core: Remove len parameter from ufshcd_set_active_icc_lvl
  ufs: core: Remove ufshcd_map_desc_id_to_length function

 drivers/ufs/core/ufs_bsg.c     |   7 +--
 drivers/ufs/core/ufshcd-priv.h |   3 --
 drivers/ufs/core/ufshcd.c      | 100 ++++++++++-------------------------------
 drivers/ufs/core/ufshpb.c      |   5 +--
 include/ufs/ufshcd.h           |   1 -
 5 files changed, 26 insertions(+), 90 deletions(-)

-- 
2.7.4