* [PATCH v2] crypto: hisilicon - allow smaller reads in debugfs
@ 2020-06-02 13:54 Dan Carpenter
2020-06-05 1:19 ` Shukun Tan
2020-06-18 7:56 ` Herbert Xu
0 siblings, 2 replies; 4+ messages in thread
From: Dan Carpenter @ 2020-06-02 13:54 UTC (permalink / raw)
To: Zhou Wang, Shukun Tan
Cc: Herbert Xu, David S. Miller, linux-crypto, linux-kernel, kernel-janitors
Originally this code rejected any read less than 256 bytes. There
is no need for this artificial limit. We should just use the normal
helper functions to read a string from the kernel.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
v2: Use simple_read_from_buffer(). The v1 was slightly half arsed
because I left the original check for:
if (*pos)
return 0;
So it could result in partial reads. The new code means that if you
want to read the buffer one byte at a time, that's fine or if you want
to read it in one 256 byte chunk that's also fine. Plus it deletes 21
lines of code and is a lot cleaner.
drivers/crypto/hisilicon/qm.c | 33 ++++++---------------------------
1 file changed, 6 insertions(+), 27 deletions(-)
diff --git a/drivers/crypto/hisilicon/qm.c b/drivers/crypto/hisilicon/qm.c
index 9bb263cec6c30..13ccb9e29a2e1 100644
--- a/drivers/crypto/hisilicon/qm.c
+++ b/drivers/crypto/hisilicon/qm.c
@@ -1064,19 +1064,10 @@ static ssize_t qm_cmd_read(struct file *filp, char __user *buffer,
char buf[QM_DBG_READ_LEN];
int len;
- if (*pos)
- return 0;
-
- if (count < QM_DBG_READ_LEN)
- return -ENOSPC;
+ len = scnprintf(buf, QM_DBG_READ_LEN, "%s\n",
+ "Please echo help to cmd to get help information");
- len = snprintf(buf, QM_DBG_READ_LEN, "%s\n",
- "Please echo help to cmd to get help information");
-
- if (copy_to_user(buffer, buf, len))
- return -EFAULT;
-
- return (*pos = len);
+ return simple_read_from_buffer(buffer, count, pos, buf, len);
}
static void *qm_ctx_alloc(struct hisi_qm *qm, size_t ctx_size,
@@ -2691,24 +2682,12 @@ static ssize_t qm_status_read(struct file *filp, char __user *buffer,
{
struct hisi_qm *qm = filp->private_data;
char buf[QM_DBG_READ_LEN];
- int val, cp_len, len;
-
- if (*pos)
- return 0;
-
- if (count < QM_DBG_READ_LEN)
- return -ENOSPC;
+ int val, len;
val = atomic_read(&qm->status.flags);
- len = snprintf(buf, QM_DBG_READ_LEN, "%s\n", qm_s[val]);
- if (!len)
- return -EFAULT;
-
- cp_len = copy_to_user(buffer, buf, len);
- if (cp_len)
- return -EFAULT;
+ len = scnprintf(buf, QM_DBG_READ_LEN, "%s\n", qm_s[val]);
- return (*pos = len);
+ return simple_read_from_buffer(buffer, count, pos, buf, len);
}
static const struct file_operations qm_status_fops = {
--
2.26.2
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH v2] crypto: hisilicon - allow smaller reads in debugfs
2020-06-02 13:54 [PATCH v2] crypto: hisilicon - allow smaller reads in debugfs Dan Carpenter
@ 2020-06-05 1:19 ` Shukun Tan
2020-06-05 9:13 ` Dan Carpenter
2020-06-18 7:56 ` Herbert Xu
1 sibling, 1 reply; 4+ messages in thread
From: Shukun Tan @ 2020-06-05 1:19 UTC (permalink / raw)
To: b6da310b-e633-9f74-f7af-7791d803aaf5, Zhou Wang
Cc: Herbert Xu, David S. Miller, linux-crypto, linux-kernel, kernel-janitors
Hi Dan,
On 2020/6/2 21:54, Dan Carpenter wrote:
> Originally this code rejected any read less than 256 bytes. There
> is no need for this artificial limit. We should just use the normal
> helper functions to read a string from the kernel.
>
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---
> v2: Use simple_read_from_buffer(). The v1 was slightly half arsed
> because I left the original check for:
>
> if (*pos)
> return 0;
>
> So it could result in partial reads. The new code means that if you
> want to read the buffer one byte at a time, that's fine or if you want
> to read it in one 256 byte chunk that's also fine. Plus it deletes 21
> lines of code and is a lot cleaner.
>
In fact, In our original design, we do not hope the user do the partial reads.
Thank you for your work, but I still insist on adding this limit.
Thanks,
Shukun
> drivers/crypto/hisilicon/qm.c | 33 ++++++---------------------------
> 1 file changed, 6 insertions(+), 27 deletions(-)
>
> diff --git a/drivers/crypto/hisilicon/qm.c b/drivers/crypto/hisilicon/qm.c
> index 9bb263cec6c30..13ccb9e29a2e1 100644
> --- a/drivers/crypto/hisilicon/qm.c
> +++ b/drivers/crypto/hisilicon/qm.c
> @@ -1064,19 +1064,10 @@ static ssize_t qm_cmd_read(struct file *filp, char __user *buffer,
> char buf[QM_DBG_READ_LEN];
> int len;
>
> - if (*pos)
> - return 0;
> -
> - if (count < QM_DBG_READ_LEN)
> - return -ENOSPC;
> + len = scnprintf(buf, QM_DBG_READ_LEN, "%s\n",
> + "Please echo help to cmd to get help information");
>
> - len = snprintf(buf, QM_DBG_READ_LEN, "%s\n",
> - "Please echo help to cmd to get help information");
> -
> - if (copy_to_user(buffer, buf, len))
> - return -EFAULT;
> -
> - return (*pos = len);
> + return simple_read_from_buffer(buffer, count, pos, buf, len);
> }
>
> static void *qm_ctx_alloc(struct hisi_qm *qm, size_t ctx_size,
> @@ -2691,24 +2682,12 @@ static ssize_t qm_status_read(struct file *filp, char __user *buffer,
> {
> struct hisi_qm *qm = filp->private_data;
> char buf[QM_DBG_READ_LEN];
> - int val, cp_len, len;
> -
> - if (*pos)
> - return 0;
> -
> - if (count < QM_DBG_READ_LEN)
> - return -ENOSPC;
> + int val, len;
>
> val = atomic_read(&qm->status.flags);
> - len = snprintf(buf, QM_DBG_READ_LEN, "%s\n", qm_s[val]);
> - if (!len)
> - return -EFAULT;
> -
> - cp_len = copy_to_user(buffer, buf, len);
> - if (cp_len)
> - return -EFAULT;
> + len = scnprintf(buf, QM_DBG_READ_LEN, "%s\n", qm_s[val]);
>
> - return (*pos = len);
> + return simple_read_from_buffer(buffer, count, pos, buf, len);
> }
>
> static const struct file_operations qm_status_fops = {
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v2] crypto: hisilicon - allow smaller reads in debugfs
2020-06-05 1:19 ` Shukun Tan
@ 2020-06-05 9:13 ` Dan Carpenter
0 siblings, 0 replies; 4+ messages in thread
From: Dan Carpenter @ 2020-06-05 9:13 UTC (permalink / raw)
To: Shukun Tan
Cc: b6da310b-e633-9f74-f7af-7791d803aaf5, Zhou Wang, Herbert Xu,
David S. Miller, linux-crypto, linux-kernel, kernel-janitors
On Fri, Jun 05, 2020 at 09:19:53AM +0800, Shukun Tan wrote:
> Hi Dan,
>
> On 2020/6/2 21:54, Dan Carpenter wrote:
> > Originally this code rejected any read less than 256 bytes. There
> > is no need for this artificial limit. We should just use the normal
> > helper functions to read a string from the kernel.
> >
> > Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> > ---
> > v2: Use simple_read_from_buffer(). The v1 was slightly half arsed
> > because I left the original check for:
> >
> > if (*pos)
> > return 0;
> >
> > So it could result in partial reads. The new code means that if you
> > want to read the buffer one byte at a time, that's fine or if you want
> > to read it in one 256 byte chunk that's also fine. Plus it deletes 21
> > lines of code and is a lot cleaner.
> >
>
> In fact, In our original design, we do not hope the user do the partial reads.
> Thank you for your work, but I still insist on adding this limit.
This not how POSIX filesystems work... :( Last time you said that this
literally breaks cat.
This doesn't break anything if the user chooses not to read a single
byte at a time. That's obviously a crazy way to read a file. It just
allows them to if they want. Or if they want to read 256 bytes at a
time then that also works. My patch makes *everything* work.
regards,
dan carpenter
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v2] crypto: hisilicon - allow smaller reads in debugfs
2020-06-02 13:54 [PATCH v2] crypto: hisilicon - allow smaller reads in debugfs Dan Carpenter
2020-06-05 1:19 ` Shukun Tan
@ 2020-06-18 7:56 ` Herbert Xu
1 sibling, 0 replies; 4+ messages in thread
From: Herbert Xu @ 2020-06-18 7:56 UTC (permalink / raw)
To: b6da310b-e633-9f74-f7af-7791d803aaf5
Cc: Zhou Wang, Shukun Tan, David S. Miller, linux-crypto,
linux-kernel, kernel-janitors
On Tue, Jun 02, 2020 at 04:54:09PM +0300, Dan Carpenter wrote:
> Originally this code rejected any read less than 256 bytes. There
> is no need for this artificial limit. We should just use the normal
> helper functions to read a string from the kernel.
>
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---
> v2: Use simple_read_from_buffer(). The v1 was slightly half arsed
> because I left the original check for:
>
> if (*pos)
> return 0;
>
> So it could result in partial reads. The new code means that if you
> want to read the buffer one byte at a time, that's fine or if you want
> to read it in one 256 byte chunk that's also fine. Plus it deletes 21
> lines of code and is a lot cleaner.
>
> drivers/crypto/hisilicon/qm.c | 33 ++++++---------------------------
> 1 file changed, 6 insertions(+), 27 deletions(-)
Patch applied. Thanks.
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
^ permalink raw reply [flat|nested] 4+ messages in thread
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