Thread (92 messages) 92 messages, 15 authors, 2020-11-10
STALE2040d

[PATCH RFC PKS/PMEM 51/58] kernel: Utilize new kmap_thread()

From: ira.weiny@intel.com
Date: 2020-10-09 19:56:42
Also in: amd-gfx, bpf, ceph-devel, dri-devel, intel-gfx, intel-wired-lan, io-uring, kexec, kvm, linux-bcache, linux-block, linux-btrfs, linux-cifs, linux-doc, linux-efi, linux-ext4, linux-f2fs-devel, linux-fsdevel, linux-kselftest, linux-mm, linux-mmc, linux-nfs, linux-rdma, linux-scsi, linux-um, linuxppc-dev, lkml, nvdimm, target-devel, xen-devel
Subsystem: kexec, the rest · Maintainers: Andrew Morton, Baoquan He, Mike Rapoport, Pasha Tatashin, Pratyush Yadav, Linus Torvalds

From: Ira Weiny <ira.weiny@intel.com>

This kmap() call is localized to a single thread.  To avoid the over
head of global PKRS updates use the new kmap_thread() call.

Cc: Eric Biederman <redacted>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
---
 kernel/kexec_core.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index c19c0dad1ebe..272a9920c0d6 100644
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -815,7 +815,7 @@ static int kimage_load_normal_segment(struct kimage *image,
 		if (result < 0)
 			goto out;
 
-		ptr = kmap(page);
+		ptr = kmap_thread(page);
 		/* Start with a clear page */
 		clear_page(ptr);
 		ptr += maddr & ~PAGE_MASK;
@@ -828,7 +828,7 @@ static int kimage_load_normal_segment(struct kimage *image,
 			memcpy(ptr, kbuf, uchunk);
 		else
 			result = copy_from_user(ptr, buf, uchunk);
-		kunmap(page);
+		kunmap_thread(page);
 		if (result) {
 			result = -EFAULT;
 			goto out;
@@ -879,7 +879,7 @@ static int kimage_load_crash_segment(struct kimage *image,
 			goto out;
 		}
 		arch_kexec_post_alloc_pages(page_address(page), 1, 0);
-		ptr = kmap(page);
+		ptr = kmap_thread(page);
 		ptr += maddr & ~PAGE_MASK;
 		mchunk = min_t(size_t, mbytes,
 				PAGE_SIZE - (maddr & ~PAGE_MASK));
@@ -895,7 +895,7 @@ static int kimage_load_crash_segment(struct kimage *image,
 		else
 			result = copy_from_user(ptr, buf, uchunk);
 		kexec_flush_icache_page(page);
-		kunmap(page);
+		kunmap_thread(page);
 		arch_kexec_pre_free_pages(page_address(page), 1);
 		if (result) {
 			result = -EFAULT;
-- 
2.28.0.rc0.12.gb6a658bd00c9
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