crypto: hisilicon/qm - allow smaller reads in debugfs
Subsystems (3)
PATCH 1/1 crypto: hisilicon/qm - allow smaller reads in debugfs
Originally this code rejected any read less than 256 bytes. There is no need for this artificial limit.
Also I have changed the snprintf() functions to scnprintf(). The difference is that snprintf() returns the number of bytes which would have been copied if there were enough space and scnprintf() returns the number of bytes which were actually copied. It doesn't matter here because the strings are very short so they can't go over 256 bytes.
--- drivers/crypto/hisilicon/qm.c | 18 ++++++++---------- 1 file changed, 8 insertions(+), 10 deletions(-)
drivers/crypto/hisilicon/qm.c +8 -10
@@ -1076,16 +1076,15 @@ static ssize_t qm_cmd_read(struct file *filp, char __user *buffer,if (*pos)return 0 ; -if (count <QM_DBG_READ_LEN ) -return -ENOSPC ; - - len =snprintf (buf,QM_DBG_READ_LEN ,"%s\n" , + len =scnprintf (buf,QM_DBG_READ_LEN ,"%s\n" ,"Please echo help to cmd to get help information" ); + len =min_t (size_t, len, count);if (copy_to_user (buffer, buf, len))return -EFAULT ; -return (*pos = len); + *pos = len; +return len; } static void *qm_ctx_alloc(struct hisi_qm *qm, size_t ctx_size,
@@ -2710,19 +2709,18 @@ static ssize_t qm_status_read(struct file *filp, char __user *buffer,if (*pos)return 0 ; -if (count <QM_DBG_READ_LEN ) -return -ENOSPC ; - val =atomic_read (&qm->status.flags); - len =snprintf (buf,QM_DBG_READ_LEN ,"%s\n" , qm_s[val]); + len =scnprintf (buf,QM_DBG_READ_LEN ,"%s\n" , qm_s[val]);if (!len)return -EFAULT ; + len =min_t (size_t, len, count); cp_len =copy_to_user (buffer, buf, len);if (cp_len)return -EFAULT ; -return (*pos = len); + *pos = len; +return len; }static const struct file_operations qm_status_fops = {
Signature · 1 line
2.26.2
Quoted 10 lines · Dan Carpenter
Originally this code rejected any read less than 256 bytes. There is no need for this artificial limit.
Also I have changed the
snprintf()functions toscnprintf(). The difference is thatsnprintf()returns the number of bytes which would have been copied if there were enough space andscnprintf()returns the number of bytes which were actually copied. It doesn't matter here because the strings are very short so they can't go over 256 bytes.Signed-off-by Dan Carpenter <[email protected]>
Looks good to me, thanks!
Quoted 54 lines
--- drivers/crypto/hisilicon/qm.c | 18 ++++++++---------- 1 file changed, 8 insertions(+), 10 deletions(-)drivers/crypto/hisilicon/qm.c +8
-10@@ -1076,16 +1076,15 @@ static ssize_t qm_cmd_read(struct file *filp, char __user *buffer,if (*pos)return 0 ; -if (count <QM_DBG_READ_LEN ) -return -ENOSPC ; - - len =snprintf (buf,QM_DBG_READ_LEN ,"%s\n" , + len =scnprintf (buf,QM_DBG_READ_LEN ,"%s\n" ,"Please echo help to cmd to get help information" ); + len =min_t (size_t, len, count);if (copy_to_user (buffer, buf, len))return -EFAULT ; -return (*pos = len); + *pos = len; +return len; } static void *qm_ctx_alloc(struct hisi_qm *qm, size_t ctx_size,@@ -2710,19 +2709,18 @@ static ssize_t qm_status_read(struct file *filp, char __user *buffer,if (*pos)return 0 ; -if (count <QM_DBG_READ_LEN ) -return -ENOSPC ; - val =atomic_read (&qm->status.flags); - len =snprintf (buf,QM_DBG_READ_LEN ,"%s\n" , qm_s[val]); + len =scnprintf (buf,QM_DBG_READ_LEN ,"%s\n" , qm_s[val]);if (!len)return -EFAULT ; + len =min_t (size_t, len, count); cp_len =copy_to_user (buffer, buf, len);if (cp_len)return -EFAULT ; -return (*pos = len); + *pos = len; +return len; }static const struct file_operations qm_status_fops = {
Hi Dan & Zhou,
Quoted 19 lines · Dan Carpenter
Originally this code rejected any read less than 256 bytes. There is no need for this artificial limit.
Also I have changed the
snprintf()functions toscnprintf(). The difference is thatsnprintf()returns the number of bytes which would have been copied if there were enough space andscnprintf()returns the number of bytes which were actually copied. It doesn't matter here because the strings are very short so they can't go over 256 bytes.Signed-off-by Dan Carpenter <[email protected]>--- drivers/crypto/hisilicon/qm.c | 18 ++++++++---------- 1 file changed, 8 insertions(+), 10 deletions(-)drivers/crypto/hisilicon/qm.c +0
-0
drivers/crypto/hisilicon/qm.c static ssize_t qm_cmd_read(struct file *filp, char __user *buffer, · line 1081
Quoted 6 lines
drivers/crypto/hisilicon/qm.c +0
-3@@ -1076,16 +1076,15 @@ static ssize_t qm_cmd_read(struct file *filp, char __user *buffer,if (*pos)return 0 ; -if (count <QM_DBG_READ_LEN ) -return -ENOSPC ; -
I think we should keep it, maybe you are right when using 'cat', but if you use 'read' system call this may make the user read only part of the prompt. This may break our original design. :)
Thanks,
Shukun
Quoted 39 lines
drivers/crypto/hisilicon/qm.c +8
-7- len =snprintf (buf,QM_DBG_READ_LEN ,"%s\n" , + len =scnprintf (buf,QM_DBG_READ_LEN ,"%s\n" ,"Please echo help to cmd to get help information" ); + len =min_t (size_t, len, count);if (copy_to_user (buffer, buf, len))return -EFAULT ; -return (*pos = len); + *pos = len; +return len; } static void *qm_ctx_alloc(struct hisi_qm *qm, size_t ctx_size,@@ -2710,19 +2709,18 @@ static ssize_t qm_status_read(struct file *filp, char __user *buffer,if (*pos)return 0 ; -if (count <QM_DBG_READ_LEN ) -return -ENOSPC ; - val =atomic_read (&qm->status.flags); - len =snprintf (buf,QM_DBG_READ_LEN ,"%s\n" , qm_s[val]); + len =scnprintf (buf,QM_DBG_READ_LEN ,"%s\n" , qm_s[val]);if (!len)return -EFAULT ; + len =min_t (size_t, len, count); cp_len =copy_to_user (buffer, buf, len);if (cp_len)return -EFAULT ; -return (*pos = len); + *pos = len; +return len; }static const struct file_operations qm_status_fops = {