Messages in this thread | | | From | Lorenzo Stoakes <> | Subject | [PATCH v3 0/4] convert read_kcore(), vread() to use iterators | Date | Mon, 20 Mar 2023 23:42:41 +0000 |
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While reviewing Baoquan's recent changes to permit vread() access to vm_map_ram regions of vmalloc allocations, Willy pointed out [1] that it would be nice to refactor vread() as a whole, since its only user is read_kcore() and the existing form of vread() necessitates the use of a bounce buffer.
This patch series does exactly that, as well as adjusting how we read the kernel text section to avoid the use of a bounce buffer in this case as well.
This has been tested against the test case which motivated Baoquan's changes in the first place [2] which continues to function correctly, as do the vmalloc self tests.
[1] https://lore.kernel.org/all/Y8WfDSRkc%2FOHP3oD@casper.infradead.org/ [2] https://lore.kernel.org/all/87ilk6gos2.fsf@oracle.com/T/#u
v3: - Revert introduction of mutex/rwsem in vmalloc - Introduce copy_page_to_iter_atomic() iovec function - Update vread_iter() and descendent functions to use only this - Fault in user pages before calling vread_iter() - Use const char* in vread_iter() and descendent functions - Updated commit messages based on feedback - Extend vread functions to always check how many bytes we could copy. If at any stage we are unable to copy/zero, abort and return the number of bytes we did copy.
v2: - Fix ordering of vread_iter() parameters - Fix nommu vread() -> vread_iter() https://lore.kernel.org/all/cover.1679209395.git.lstoakes@gmail.com/
v1: https://lore.kernel.org/all/cover.1679183626.git.lstoakes@gmail.com/
Lorenzo Stoakes (4): fs/proc/kcore: Avoid bounce buffer for ktext data fs/proc/kcore: convert read_kcore() to read_kcore_iter() iov_iter: add copy_page_to_iter_atomic() mm: vmalloc: convert vread() to vread_iter()
fs/proc/kcore.c | 89 ++++++--------- include/linux/uio.h | 2 + include/linux/vmalloc.h | 3 +- lib/iov_iter.c | 28 +++++ mm/nommu.c | 10 +- mm/vmalloc.c | 234 +++++++++++++++++++++++++--------------- 6 files changed, 218 insertions(+), 148 deletions(-)
-- 2.39.2
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