equivalence of pread in linux kernel space (with O_DIRECT)

Question

I am working with systemtap probe which is in linux kernel space and so I can't use the regular pread syscall. Is there a equivalence of pread syscall in kernel space?

my friend found this: http://lxr.free-electrons.com/source/fs/read_write.c?v=2.6.32#L433 but what is the header file that I need to include?

Thanks!

Erben

score 0 · Accepted Answer · answered Dec 04 '14 at 08:32

0

The pread system call is actually calling vfs_read(), so you can use vfs_read() in the kernel space.

vfs_read is an exported symbol and you don't need to include any header file.

answered Dec 04 '14 at 08:32

Brienza

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Thanks! another thing, vfs_read seems to only take a buffer in user space. If a do a kmalloc and pass the buffer to vfs_read, it returns EFAULT. Is there a way for me to get a user_space memory from kernel_space? – Erben Mo Dec 11 '14 at 00:58
http://stackoverflow.com/questions/7629141/allocate-user-space-memory-from-kernel – Erben Mo Dec 11 '14 at 01:12

equivalence of pread in linux kernel space (with O_DIRECT)

1 Answers1