The patch titled
Subject: nios2: fix flush_dcache_page() for usage from irq context
has been added to the -mm mm-nonmm-unstable branch. Its filename is
nios2-fix-flush_dcache_page-for-usage-from-irq-context.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/nios2-fix-flush_dcache_page-for-usage-from-irq-context.patch
This patch will later appear in the mm-nonmm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Helge Deller <deller@xxxxxx>
Subject: nios2: fix flush_dcache_page() for usage from irq context
Date: Tue, 22 Aug 2023 16:27:49 +0200
Since at least kernel 6.1, flush_dcache_page() is called with IRQs
disabled, e.g. from aio_complete().
But the current implementation for flush_dcache_page() on NIOS2
unintentionally re-enables IRQs, which may lead to deadlocks.
Fix it by using xa_lock_irqsave() and xa_unlock_irqrestore() for the
flush_dcache_mmap_*lock() macros instead.
Link: https://lkml.kernel.org/r/ZOTF5WWURQNH9+iw@p100
Signed-off-by: Helge Deller <deller@xxxxxx>
Cc: Dinh Nguyen <dinguyen@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/nios2/include/asm/cacheflush.h | 4 ++++
arch/nios2/mm/cacheflush.c | 5 +++--
2 files changed, 7 insertions(+), 2 deletions(-)
--- a/arch/nios2/include/asm/cacheflush.h~nios2-fix-flush_dcache_page-for-usage-from-irq-context
+++ a/arch/nios2/include/asm/cacheflush.h
@@ -52,5 +52,9 @@ extern void invalidate_dcache_range(unsi
#define flush_dcache_mmap_lock(mapping) xa_lock_irq(&mapping->i_pages)
#define flush_dcache_mmap_unlock(mapping) xa_unlock_irq(&mapping->i_pages)
+#define flush_dcache_mmap_lock_irqsave(mapping, flags) \
+ xa_lock_irqsave(&mapping->i_pages, flags)
+#define flush_dcache_mmap_unlock_irqrestore(mapping, flags) \
+ xa_unlock_irqrestore(&mapping->i_pages, flags)
#endif /* _ASM_NIOS2_CACHEFLUSH_H */
--- a/arch/nios2/mm/cacheflush.c~nios2-fix-flush_dcache_page-for-usage-from-irq-context
+++ a/arch/nios2/mm/cacheflush.c
@@ -75,12 +75,13 @@ static void flush_aliases(struct address
{
struct mm_struct *mm = current->active_mm;
struct vm_area_struct *vma;
+ unsigned long flags;
pgoff_t pgoff;
unsigned long nr = folio_nr_pages(folio);
pgoff = folio->index;
- flush_dcache_mmap_lock(mapping);
+ flush_dcache_mmap_lock_irqsave(mapping, flags);
vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff + nr - 1) {
unsigned long start;
@@ -92,7 +93,7 @@ static void flush_aliases(struct address
start = vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT);
flush_cache_range(vma, start, start + nr * PAGE_SIZE);
}
- flush_dcache_mmap_unlock(mapping);
+ flush_dcache_mmap_unlock_irqrestore(mapping, flags);
}
void flush_cache_all(void)
_
Patches currently in -mm which might be from deller@xxxxxx are
nios2-fix-flush_dcache_page-for-usage-from-irq-context.patch
