[PATCH v2 3/4] scsi: ufs: Refactor descriptor read for write
From: Evan Green
Date: Fri Jun 15 2018 - 17:02:38 EST
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@xxxxxxxxxxxx>
---
Changes since v1:
- Fail if requesting a region fully outside the descriptor.
- Clear the remaining buffer if requesting a region partially
outside the descriptor.
- Add a mutex around the read-modify-write operation as
suggested by Bart.
- Fixed comment style in this function as suggested by Bart.
- Refactored error prints to the end of the function, which I
think addresses the appearance that the function is nested too deeply
(as it only actually has 3 levels of nesting).
drivers/scsi/ufs/ufs-sysfs.c | 4 +-
drivers/scsi/ufs/ufshcd.c | 109 +++++++++++++++++++++++++++++++------------
drivers/scsi/ufs/ufshcd.h | 15 +++---
3 files changed, 90 insertions(+), 38 deletions(-)
diff --git a/drivers/scsi/ufs/ufs-sysfs.c b/drivers/scsi/ufs/ufs-sysfs.c
index 4726c05bb085..d0365e8bf839 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 0baba3fdb112..110157877823 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -3092,22 +3092,24 @@ 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;
@@ -3118,7 +3120,8 @@ int ufshcd_read_desc_param(struct ufs_hba *hba,
if (desc_id >= QUERY_DESC_IDN_MAX || !param_size)
return -EINVAL;
- /* Get the max length of descriptor from structure filled up at probe
+ /*
+ * Get the max length of descriptor from structure filled up at probe
* time.
*/
ret = ufshcd_map_desc_id_to_length(hba, desc_id, &buff_len);
@@ -3130,26 +3133,53 @@ int ufshcd_read_desc_param(struct ufs_hba *hba,
return ret;
}
+ if (param_offset > buff_len)
+ return -EINVAL;
+
+ /* Lock the descriptor mutex to prevent simultaneous changes. */
+ mutex_lock(&hba->desc_mutex);
+
/* Check whether we need temp memory */
if (param_offset != 0 || param_size < buff_len) {
- desc_buf = kmalloc(buff_len, GFP_KERNEL);
- if (!desc_buf)
- return -ENOMEM;
+ desc_buf = kzalloc(buff_len, GFP_KERNEL);
+ if (!desc_buf) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ /*
+ * 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 (param_offset + 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)
+ 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);
+ if (ret)
goto out;
- }
/* Sanity check */
if (desc_buf[QUERY_DESC_DESC_TYPE_OFFSET] != desc_id) {
@@ -3159,13 +3189,29 @@ 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 (param_offset + param_size > buff_len) {
+ memset(param_buf + buff_len - param_offset, 0,
+ param_offset + 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:
+ mutex_unlock(&hba->desc_mutex);
+ if (ret)
+ dev_err(hba->dev, "Failed %s descriptor. desc_id %d, desc_index %d, param_offset %d, ret %d",
+ opcode == UPIU_QUERY_OPCODE_READ_DESC ?
+ "reading" : "writing",
+ desc_id, desc_index, param_offset, ret);
+
if (is_kmalloc)
kfree(desc_buf);
return ret;
@@ -3177,7 +3223,8 @@ 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,
@@ -3283,8 +3330,9 @@ 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);
}
/**
@@ -8019,8 +8067,9 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq)
INIT_WORK(&hba->eh_work, ufshcd_err_handler);
INIT_WORK(&hba->eeh_work, ufshcd_exception_event_handler);
- /* Initialize UIC command mutex */
+ /* Initialize UIC command and descriptor mutexes */
mutex_init(&hba->uic_cmd_mutex);
+ mutex_init(&hba->desc_mutex);
/* Initialize mutex for device management commands */
mutex_init(&hba->dev_cmd.lock);
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index bb540a3fd8de..c6305a458100 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -513,6 +513,7 @@ struct ufs_cfg_object {
* @scsi_block_reqs_cnt: reference counting for scsi block requests
* @cfg_objects: Stores the array of kobjects created for the config descriptor.
* @cfg_object_count: Stores the number of elements in cfg_objects.
+ * @desc_mutex: Mutex to serialize modifications to UFS descriptors.
*/
struct ufs_hba {
void __iomem *mmio_base;
@@ -717,6 +718,7 @@ struct ufs_hba {
struct ufs_cfg_object **cfg_objects;
size_t cfg_object_count;
+ struct mutex desc_mutex;
};
/* Returns true if clocks can be gated. Otherwise false */
@@ -886,12 +888,13 @@ 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_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