Phillip Lougher <[EMAIL PROTECTED]> wrote:
+skip_read: + memset(pageaddr + bytes, 0, PAGE_CACHE_SIZE - bytes); + kunmap(page); + flush_dcache_page(page); + SetPageUptodate(page); + unlock_page(page); + + return 0; +}
See if you can use kmap_atomic() here - kmap() is slow, theoretically deadlocky and is deprecated.
From some browsing of the kernel source and a useful article on lwn.net I think I can replace all the readpage_xxx (symlink, readpage & readpage4k) kmap/kunmaps with kmap_atomic(page, KM_USER0)/kunmap(kaddr, KM_USER0)...
The lwn.net article mentions that k[un]map_atomic is the new alternative to kmap (as Andrew Morton mentioned).
I've noticed in asm-ppc/highmem.h the following comment
/* * The use of kmap_atomic/kunmap_atomic is discouraged - kmap/kunmap * gives a more generic (and caching) interface. But kmap_atomic can * be used in IRQ contexts, so in some (very limited) cases we need * it. */
Given what Andrew and the lwn.net article says, this comment is rather confusing. Is it wrong?
Regards
Phillip Lougher - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
