parisc: Fix flush_dcache_page() for usage from irq context

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 parisc
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.

Cc: linux-parisc@vger.kernel.org
Cc: stable@kernel.org # 5.18+
Signed-off-by: Helge Deller <deller@gmx.de>

diff --git a/arch/parisc/include/asm/cacheflush.h b/arch/parisc/include/asm/cacheflush.h
index 0bdee67..c8b6928 100644 (file)
--- a/arch/parisc/include/asm/cacheflush.h
+++ b/arch/parisc/include/asm/cacheflush.h
@@ -48,6 +48,10 @@ void flush_dcache_page(struct page *page);
 
 #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)
 
 #define flush_icache_page(vma,page)    do {            \
        flush_kernel_dcache_page_addr(page_address(page)); \

diff --git a/arch/parisc/kernel/cache.c b/arch/parisc/kernel/cache.c
index 1d3b8bc..ca4a302 100644 (file)
--- a/arch/parisc/kernel/cache.c
+++ b/arch/parisc/kernel/cache.c
@@ -399,6 +399,7 @@ void flush_dcache_page(struct page *page)
        unsigned long offset;
        unsigned long addr, old_addr = 0;
        unsigned long count = 0;
+       unsigned long flags;
        pgoff_t pgoff;
 
        if (mapping && !mapping_mapped(mapping)) {
@@ -420,7 +421,7 @@ void flush_dcache_page(struct page *page)
         * to flush one address here for them all to become coherent
         * on machines that support equivalent aliasing
         */
-       flush_dcache_mmap_lock(mapping);
+       flush_dcache_mmap_lock_irqsave(mapping, flags);
        vma_interval_tree_foreach(mpnt, &mapping->i_mmap, pgoff, pgoff) {
                offset = (pgoff - mpnt->vm_pgoff) << PAGE_SHIFT;
                addr = mpnt->vm_start + offset;
@@ -460,7 +461,7 @@ void flush_dcache_page(struct page *page)
                }
                WARN_ON(++count == 4096);
        }
-       flush_dcache_mmap_unlock(mapping);
+       flush_dcache_mmap_unlock_irqrestore(mapping, flags);
 }
 EXPORT_SYMBOL(flush_dcache_page);