Merge tag 'dma-mapping-6.6-2023-09-09' of git://git.infradead.org/users/hch/dma-mapping

Pull dma-mapping fixes from Christoph Hellwig:

 - move a dma-debug call that prints a message out from a lock that's
   causing problems with the lock order in serial drivers (Sergey
   Senozhatsky)

 - fix the CONFIG_DMA_NUMA_CMA Kconfig entry to have the right
   dependency and not default to y (Christoph Hellwig)

 - move an ifdef a bit to remove a __maybe_unused that seems to trip up
   some sensitivities (Christoph Hellwig)

 - revert a bogus check in the CMA allocator (Zhenhua Huang)

* tag 'dma-mapping-6.6-2023-09-09' of git://git.infradead.org/users/hch/dma-mapping:
  Revert "dma-contiguous: check for memory region overlap"
  dma-pool: remove a __maybe_unused label in atomic_pool_expand
  dma-contiguous: fix the Kconfig entry for CONFIG_DMA_NUMA_CMA
  dma-debug: don't call __dma_entry_alloc_check_leak() under free_entries_lock

diff --git a/kernel/dma/Kconfig b/kernel/dma/Kconfig
index 4c1e9a3..f488997 100644 (file)
--- a/kernel/dma/Kconfig
+++ b/kernel/dma/Kconfig
@@ -160,7 +160,7 @@ if  DMA_CMA
 
 config DMA_NUMA_CMA
        bool "Enable separate DMA Contiguous Memory Area for NUMA Node"
-       default NUMA
+       depends on NUMA
        help
          Enable this option to get numa CMA areas so that NUMA devices
          can get local memory by DMA coherent APIs.

diff --git a/kernel/dma/contiguous.c b/kernel/dma/contiguous.c
index 88c595e..f005c66 100644 (file)
--- a/kernel/dma/contiguous.c
+++ b/kernel/dma/contiguous.c
@@ -473,11 +473,6 @@ static int __init rmem_cma_setup(struct reserved_mem *rmem)
                return -EBUSY;
        }
 
-       if (memblock_is_region_reserved(rmem->base, rmem->size)) {
-               pr_info("Reserved memory: overlap with other memblock reserved region\n");
-               return -EBUSY;
-       }
-
        if (!of_get_flat_dt_prop(node, "reusable", NULL) ||
            of_get_flat_dt_prop(node, "no-map", NULL))
                return -EINVAL;

diff --git a/kernel/dma/debug.c b/kernel/dma/debug.c
index f190651..06366ac 100644 (file)
--- a/kernel/dma/debug.c
+++ b/kernel/dma/debug.c
@@ -637,15 +637,19 @@ static struct dma_debug_entry *__dma_entry_alloc(void)
        return entry;
 }
 
-static void __dma_entry_alloc_check_leak(void)
+/*
+ * This should be called outside of free_entries_lock scope to avoid potential
+ * deadlocks with serial consoles that use DMA.
+ */
+static void __dma_entry_alloc_check_leak(u32 nr_entries)
 {
-       u32 tmp = nr_total_entries % nr_prealloc_entries;
+       u32 tmp = nr_entries % nr_prealloc_entries;
 
        /* Shout each time we tick over some multiple of the initial pool */
        if (tmp < DMA_DEBUG_DYNAMIC_ENTRIES) {
                pr_info("dma_debug_entry pool grown to %u (%u00%%)\n",
-                       nr_total_entries,
-                       (nr_total_entries / nr_prealloc_entries));
+                       nr_entries,
+                       (nr_entries / nr_prealloc_entries));
        }
 }
 
@@ -656,8 +660,10 @@ static void __dma_entry_alloc_check_leak(void)
  */
 static struct dma_debug_entry *dma_entry_alloc(void)
 {
+       bool alloc_check_leak = false;
        struct dma_debug_entry *entry;
        unsigned long flags;
+       u32 nr_entries;
 
        spin_lock_irqsave(&free_entries_lock, flags);
        if (num_free_entries == 0) {
@@ -667,13 +673,17 @@ static struct dma_debug_entry *dma_entry_alloc(void)
                        pr_err("debugging out of memory - disabling\n");
                        return NULL;
                }
-               __dma_entry_alloc_check_leak();
+               alloc_check_leak = true;
+               nr_entries = nr_total_entries;
        }
 
        entry = __dma_entry_alloc();
 
        spin_unlock_irqrestore(&free_entries_lock, flags);
 
+       if (alloc_check_leak)
+               __dma_entry_alloc_check_leak(nr_entries);
+
 #ifdef CONFIG_STACKTRACE
        entry->stack_len = stack_trace_save(entry->stack_entries,
                                            ARRAY_SIZE(entry->stack_entries),

diff --git a/kernel/dma/pool.c b/kernel/dma/pool.c
index 1acec2e..b481c48 100644 (file)
--- a/kernel/dma/pool.c
+++ b/kernel/dma/pool.c
@@ -135,9 +135,9 @@ encrypt_mapping:
 remove_mapping:
 #ifdef CONFIG_DMA_DIRECT_REMAP
        dma_common_free_remap(addr, pool_size);
-#endif
-free_page: __maybe_unused
+free_page:
        __free_pages(page, order);
+#endif
 out:
        return ret;
 }