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Subject[PATCH 5/7] scsi: ufs: Refactor descriptor read for write
Date
This change refactors the ufshcd_read_desc_param function into
one that can both read and write descriptors. Most of the low-level
plumbing for writing to descriptors was already there, this change
simply enables that code path, and manages the incoming data buffer
appropriately.

Signed-off-by: Evan Green <evgreen@chromium.org>
---
drivers/scsi/ufs/ufs-sysfs.c | 4 +-
drivers/scsi/ufs/ufshcd.c | 89 ++++++++++++++++++++++++++++++++------------
drivers/scsi/ufs/ufshcd.h | 13 ++++---
3 files changed, 74 insertions(+), 32 deletions(-)

diff --git a/drivers/scsi/ufs/ufs-sysfs.c b/drivers/scsi/ufs/ufs-sysfs.c
index 51bf54e6b47a..623c56074572 100644
--- a/drivers/scsi/ufs/ufs-sysfs.c
+++ b/drivers/scsi/ufs/ufs-sysfs.c
@@ -227,8 +227,8 @@ static ssize_t ufs_sysfs_read_desc_param(struct ufs_hba *hba,
if (param_size > 8)
return -EINVAL;

- ret = ufshcd_read_desc_param(hba, desc_id, desc_index,
- param_offset, desc_buf, param_size);
+ ret = ufshcd_rw_desc_param(hba, UPIU_QUERY_OPCODE_READ_DESC, desc_id,
+ desc_index, param_offset, desc_buf, param_size);
if (ret)
return -EINVAL;
switch (param_size) {
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 00e79057f870..6a5939fb5da3 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -3004,22 +3004,24 @@ int ufshcd_map_desc_id_to_length(struct ufs_hba *hba,
EXPORT_SYMBOL(ufshcd_map_desc_id_to_length);

/**
- * ufshcd_read_desc_param - read the specified descriptor parameter
+ * ufshcd_rw_desc_param - read or write the specified descriptor parameter
* @hba: Pointer to adapter instance
+ * @opcode: indicates whether to read or write
* @desc_id: descriptor idn value
* @desc_index: descriptor index
- * @param_offset: offset of the parameter to read
- * @param_read_buf: pointer to buffer where parameter would be read
- * @param_size: sizeof(param_read_buf)
+ * @param_offset: offset of the parameter to read or write
+ * @param_buf: pointer to buffer to be read or written
+ * @param_size: sizeof(param_buf)
*
* Return 0 in case of success, non-zero otherwise
*/
-int ufshcd_read_desc_param(struct ufs_hba *hba,
- enum desc_idn desc_id,
- int desc_index,
- u8 param_offset,
- u8 *param_read_buf,
- u8 param_size)
+int ufshcd_rw_desc_param(struct ufs_hba *hba,
+ enum query_opcode opcode,
+ enum desc_idn desc_id,
+ int desc_index,
+ u8 param_offset,
+ u8 *param_buf,
+ u8 param_size)
{
int ret;
u8 *desc_buf;
@@ -3042,24 +3044,57 @@ int ufshcd_read_desc_param(struct ufs_hba *hba,
return ret;
}

+ if (param_offset > buff_len)
+ return 0;
+
/* Check whether we need temp memory */
if (param_offset != 0 || param_size < buff_len) {
- desc_buf = kmalloc(buff_len, GFP_KERNEL);
+ desc_buf = kzalloc(buff_len, GFP_KERNEL);
if (!desc_buf)
return -ENOMEM;
+
+ /* If it's a write, first read the complete descriptor, then
+ * copy in the parts being changed.
+ */
+ if (opcode == UPIU_QUERY_OPCODE_WRITE_DESC) {
+ if ((int)param_offset + (int)param_size > buff_len) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ ret = ufshcd_query_descriptor_retry(hba,
+ UPIU_QUERY_OPCODE_READ_DESC,
+ 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",
+ __func__, desc_id, desc_index,
+ param_offset, ret);
+
+ goto out;
+ }
+
+ memcpy(desc_buf + param_offset, param_buf, param_size);
+ }
+
} else {
- desc_buf = param_read_buf;
+ desc_buf = param_buf;
is_kmalloc = false;
}

- /* Request for full descriptor */
- ret = ufshcd_query_descriptor_retry(hba, UPIU_QUERY_OPCODE_READ_DESC,
+ /* Read or write the entire descriptor. */
+ ret = ufshcd_query_descriptor_retry(hba, opcode,
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",
- __func__, desc_id, desc_index, param_offset, ret);
+ dev_err(hba->dev, "%s: Failed %s descriptor. desc_id %d, desc_index %d, param_offset %d, ret %d",
+ __func__,
+ opcode == UPIU_QUERY_OPCODE_READ_DESC ?
+ "reading" : "writing",
+ desc_id, desc_index, param_offset, ret);
goto out;
}

@@ -3071,12 +3106,16 @@ int ufshcd_read_desc_param(struct ufs_hba *hba,
goto out;
}

- /* Check wherher we will not copy more data, than available */
- if (is_kmalloc && param_size > buff_len)
- param_size = buff_len;
+ /* Copy data to the output. The offset is already validated to be
+ * within the buffer.
+ */
+ if (is_kmalloc && (opcode == UPIU_QUERY_OPCODE_READ_DESC)) {
+ if ((int)param_offset + (int)param_size > buff_len)
+ param_size = buff_len - param_offset;
+
+ memcpy(param_buf, &desc_buf[param_offset], param_size);
+ }

- if (is_kmalloc)
- memcpy(param_read_buf, &desc_buf[param_offset], param_size);
out:
if (is_kmalloc)
kfree(desc_buf);
@@ -3089,7 +3128,8 @@ static inline int ufshcd_read_desc(struct ufs_hba *hba,
u8 *buf,
u32 size)
{
- return ufshcd_read_desc_param(hba, desc_id, desc_index, 0, buf, size);
+ return ufshcd_rw_desc_param(hba, UPIU_QUERY_OPCODE_READ_DESC, desc_id,
+ desc_index, 0, buf, size);
}

static inline int ufshcd_read_power_desc(struct ufs_hba *hba,
@@ -3195,8 +3235,9 @@ static inline int ufshcd_read_unit_desc_param(struct ufs_hba *hba,
if (!ufs_is_valid_unit_desc_lun(lun))
return -EOPNOTSUPP;

- return ufshcd_read_desc_param(hba, QUERY_DESC_IDN_UNIT, lun,
- param_offset, param_read_buf, param_size);
+ return ufshcd_rw_desc_param(hba, UPIU_QUERY_OPCODE_READ_DESC,
+ QUERY_DESC_IDN_UNIT, lun, param_offset,
+ param_read_buf, param_size);
}

/**
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index fb6dcc490f21..ebbd9d580c4b 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -853,12 +853,13 @@ int ufshcd_query_descriptor_retry(struct ufs_hba *hba,
enum desc_idn idn, u8 index,
u8 selector,
u8 *desc_buf, int *buf_len);
-int ufshcd_read_desc_param(struct ufs_hba *hba,
- enum desc_idn desc_id,
- int desc_index,
- u8 param_offset,
- u8 *param_read_buf,
- u8 param_size);
+int ufshcd_rw_desc_param(struct ufs_hba *hba,
+ enum query_opcode opcode,
+ enum desc_idn desc_id,
+ int desc_index,
+ u8 param_offset,
+ u8 *param_read_buf,
+ u8 param_size);
int ufshcd_query_attr(struct ufs_hba *hba, enum query_opcode opcode,
enum attr_idn idn, u8 index, u8 selector, u32 *attr_val);
int ufshcd_query_flag(struct ufs_hba *hba, enum query_opcode opcode,
--
2.13.5
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