[PATCH] KVM: set no_llseek in stat_fops_per_vm

[PATCH] KVM: set no_llseek in stat_fops_per_vm

[Geliang Tang]

In vm_stat_get_per_vm_fops and vcpu_stat_get_per_vm_fops, since we
use nonseekable_open() to open, we should use no_llseek() to seek,
not generic_file_llseek().

Signed-off-by: Geliang Tang <geliangtang@gmail.com>
---
 virt/kvm/kvm_main.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index c2bb6ab..798f567 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -3689,7 +3689,7 @@ static const struct file_operations vm_stat_get_per_vm_fops = {
 	.release = kvm_debugfs_release,
 	.read    = simple_attr_read,
 	.write   = simple_attr_write,
-	.llseek  = generic_file_llseek,
+	.llseek  = no_llseek,
 };
 
 static int vcpu_stat_get_per_vm(void *data, u64 *val)
@@ -3734,7 +3734,7 @@ static const struct file_operations vcpu_stat_get_per_vm_fops = {
 	.release = kvm_debugfs_release,
 	.read    = simple_attr_read,
 	.write   = simple_attr_write,
-	.llseek  = generic_file_llseek,
+	.llseek  = no_llseek,
 };
 
 static const struct file_operations *stat_fops_per_vm[] = {
-- 
2.9.3

[PATCH] powerpc/cell: set no_llseek in spufs_cntl_fops

[Geliang Tang]

In spufs_cntl_fops, since we use nonseekable_open() to open, we
should use no_llseek() to seek, not generic_file_llseek().

Signed-off-by: Geliang Tang <geliangtang@gmail.com>
---
 arch/powerpc/platforms/cell/spufs/file.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/platforms/cell/spufs/file.c b/arch/powerpc/platforms/cell/spufs/file.c
index ae2f740..738ef8d 100644
--- a/arch/powerpc/platforms/cell/spufs/file.c
+++ b/arch/powerpc/platforms/cell/spufs/file.c
@@ -456,7 +456,7 @@ static const struct file_operations spufs_cntl_fops = {
 	.release = spufs_cntl_release,
 	.read = simple_attr_read,
 	.write = simple_attr_write,
-	.llseek	= generic_file_llseek,
+	.llseek	= no_llseek,
 	.mmap = spufs_cntl_mmap,
 };
 
-- 
2.9.3

Re: [PATCH] powerpc/cell: set no_llseek in spufs_cntl_fops

[Michael Ellerman]

On Sat, 2017-05-06 at 15:37:20 UTC, Geliang Tang wrote:
> In spufs_cntl_fops, since we use nonseekable_open() to open, we
> should use no_llseek() to seek, not generic_file_llseek().
> 
> Signed-off-by: Geliang Tang <geliangtang@gmail.com>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/658829dfe75c49e879e0c4c9cbcd3bd1e4fbdcf5

cheers

Re: [PATCH] KVM: set no_llseek in stat_fops_per_vm

[Paolo Bonzini]

On 06/05/2017 17:37, Geliang Tang wrote:
> In vm_stat_get_per_vm_fops and vcpu_stat_get_per_vm_fops, since we
> use nonseekable_open() to open, we should use no_llseek() to seek,
> not generic_file_llseek().
> 
> Signed-off-by: Geliang Tang <geliangtang@gmail.com>

This is not strictly necessary, nonseekable_open bypasses f_op->llseek
due to this code in vfs_llseek:

        fn = no_llseek;
        if (file->f_mode & FMODE_LSEEK) {
                if (file->f_op->llseek)
                        fn = file->f_op->llseek;
        }
        return fn(file, offset, whence);

But it's a good thing to do anyway, so I'm applying it.

Paolo

> ---
>  virt/kvm/kvm_main.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index c2bb6ab..798f567 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -3689,7 +3689,7 @@ static const struct file_operations vm_stat_get_per_vm_fops = {
>  	.release = kvm_debugfs_release,
>  	.read    = simple_attr_read,
>  	.write   = simple_attr_write,
> -	.llseek  = generic_file_llseek,
> +	.llseek  = no_llseek,
>  };
>  
>  static int vcpu_stat_get_per_vm(void *data, u64 *val)
> @@ -3734,7 +3734,7 @@ static const struct file_operations vcpu_stat_get_per_vm_fops = {
>  	.release = kvm_debugfs_release,
>  	.read    = simple_attr_read,
>  	.write   = simple_attr_write,
> -	.llseek  = generic_file_llseek,
> +	.llseek  = no_llseek,
>  };
>  
>  static const struct file_operations *stat_fops_per_vm[] = {
>