5 files changed, 167 insertions, 53 deletions

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index ba106db5a65b..882c51048993 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -150,7 +150,7 @@ config DETECT_SOFTLOCKUP
         help
           Say Y here to enable the kernel to detect "soft lockups",
           which are bugs that cause the kernel to loop in kernel
-          mode for more than 10 seconds, without giving other tasks a
+          mode for more than 60 seconds, without giving other tasks a
           chance to run.
 
           When a soft-lockup is detected, the kernel will print the
@@ -162,6 +162,30 @@ config DETECT_SOFTLOCKUP
            can be detected via the NMI-watchdog, on platforms that
            support it.)
 
+config BOOTPARAM_SOFTLOCKUP_PANIC
+        bool "Panic (Reboot) On Soft Lockups"
+        depends on DETECT_SOFTLOCKUP
+        help
+          Say Y here to enable the kernel to panic on "soft lockups",
+          which are bugs that cause the kernel to loop in kernel
+          mode for more than 60 seconds, without giving other tasks a
+          chance to run.
+
+          The panic can be used in combination with panic_timeout,
+          to cause the system to reboot automatically after a
+          lockup has been detected. This feature is useful for
+          high-availability systems that have uptime guarantees and
+          where a lockup must be resolved ASAP.
+
+          Say N if unsure.
+
+config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
+        int
+        depends on DETECT_SOFTLOCKUP
+        range 0 1
+        default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
+        default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
+
 config SCHED_DEBUG
         bool "Collect scheduler debugging info"
         depends on DEBUG_KERNEL && PROC_FS
diff --git a/lib/Kconfig.kgdb b/lib/Kconfig.kgdb
index a5d4b1dac2a5..2cfd2721f7ed 100644
--- a/lib/Kconfig.kgdb
+++ b/lib/Kconfig.kgdb
@@ -1,7 +1,4 @@
 
-config HAVE_ARCH_KGDB_SHADOW_INFO
-        bool
-
 config HAVE_ARCH_KGDB
         bool
 
diff --git a/lib/cpumask.c b/lib/cpumask.c
index bb4f76d3c3e7..5f97dc25ef9c 100644
--- a/lib/cpumask.c
+++ b/lib/cpumask.c
@@ -15,6 +15,15 @@ int __next_cpu(int n, const cpumask_t *srcp)
 }
 EXPORT_SYMBOL(__next_cpu);
 
+#if NR_CPUS > 64
+int __next_cpu_nr(int n, const cpumask_t *srcp)
+{
+        return min_t(int, nr_cpu_ids,
+                                find_next_bit(srcp->bits, nr_cpu_ids, n+1));
+}
+EXPORT_SYMBOL(__next_cpu_nr);
+#endif
+
 int __any_online_cpu(const cpumask_t *mask)
 {
         int cpu;
diff --git a/lib/scatterlist.c b/lib/scatterlist.c
index b80c21100d78..876ba6d5b670 100644
--- a/lib/scatterlist.c
+++ b/lib/scatterlist.c
@@ -295,6 +295,117 @@ int sg_alloc_table(struct sg_table *table, unsigned int nents, gfp_t gfp_mask)
 EXPORT_SYMBOL(sg_alloc_table);
 
 /**
+ * sg_miter_start - start mapping iteration over a sg list
+ * @miter: sg mapping iter to be started
+ * @sgl: sg list to iterate over
+ * @nents: number of sg entries
+ *
+ * Description:
+ *   Starts mapping iterator @miter.
+ *
+ * Context:
+ *   Don't care.
+ */
+void sg_miter_start(struct sg_mapping_iter *miter, struct scatterlist *sgl,
+                    unsigned int nents, unsigned int flags)
+{
+        memset(miter, 0, sizeof(struct sg_mapping_iter));
+
+        miter->__sg = sgl;
+        miter->__nents = nents;
+        miter->__offset = 0;
+        miter->__flags = flags;
+}
+EXPORT_SYMBOL(sg_miter_start);
+
+/**
+ * sg_miter_next - proceed mapping iterator to the next mapping
+ * @miter: sg mapping iter to proceed
+ *
+ * Description:
+ *   Proceeds @miter@ to the next mapping.  @miter@ should have been
+ *   started using sg_miter_start().  On successful return,
+ *   @miter@->page, @miter@->addr and @miter@->length point to the
+ *   current mapping.
+ *
+ * Context:
+ *   IRQ disabled if SG_MITER_ATOMIC.  IRQ must stay disabled till
+ *   @miter@ is stopped.  May sleep if !SG_MITER_ATOMIC.
+ *
+ * Returns:
+ *   true if @miter contains the next mapping.  false if end of sg
+ *   list is reached.
+ */
+bool sg_miter_next(struct sg_mapping_iter *miter)
+{
+        unsigned int off, len;
+
+        /* check for end and drop resources from the last iteration */
+        if (!miter->__nents)
+                return false;
+
+        sg_miter_stop(miter);
+
+        /* get to the next sg if necessary.  __offset is adjusted by stop */
+        if (miter->__offset == miter->__sg->length && --miter->__nents) {
+                miter->__sg = sg_next(miter->__sg);
+                miter->__offset = 0;
+        }
+
+        /* map the next page */
+        off = miter->__sg->offset + miter->__offset;
+        len = miter->__sg->length - miter->__offset;
+
+        miter->page = nth_page(sg_page(miter->__sg), off >> PAGE_SHIFT);
+        off &= ~PAGE_MASK;
+        miter->length = min_t(unsigned int, len, PAGE_SIZE - off);
+        miter->consumed = miter->length;
+
+        if (miter->__flags & SG_MITER_ATOMIC)
+                miter->addr = kmap_atomic(miter->page, KM_BIO_SRC_IRQ) + off;
+        else
+                miter->addr = kmap(miter->page) + off;
+
+        return true;
+}
+EXPORT_SYMBOL(sg_miter_next);
+
+/**
+ * sg_miter_stop - stop mapping iteration
+ * @miter: sg mapping iter to be stopped
+ *
+ * Description:
+ *   Stops mapping iterator @miter.  @miter should have been started
+ *   started using sg_miter_start().  A stopped iteration can be
+ *   resumed by calling sg_miter_next() on it.  This is useful when
+ *   resources (kmap) need to be released during iteration.
+ *
+ * Context:
+ *   IRQ disabled if the SG_MITER_ATOMIC is set.  Don't care otherwise.
+ */
+void sg_miter_stop(struct sg_mapping_iter *miter)
+{
+        WARN_ON(miter->consumed > miter->length);
+
+        /* drop resources from the last iteration */
+        if (miter->addr) {
+                miter->__offset += miter->consumed;
+
+                if (miter->__flags & SG_MITER_ATOMIC) {
+                        WARN_ON(!irqs_disabled());
+                        kunmap_atomic(miter->addr, KM_BIO_SRC_IRQ);
+                } else
+                        kunmap(miter->addr);
+
+                miter->page = NULL;
+                miter->addr = NULL;
+                miter->length = 0;
+                miter->consumed = 0;
+        }
+}
+EXPORT_SYMBOL(sg_miter_stop);
+
+/**
  * sg_copy_buffer - Copy data between a linear buffer and an SG list
  * @sgl:                 The SG list
  * @nents:               Number of SG entries
@@ -309,56 +420,29 @@ EXPORT_SYMBOL(sg_alloc_table);
 static size_t sg_copy_buffer(struct scatterlist *sgl, unsigned int nents,
                              void *buf, size_t buflen, int to_buffer)
 {
-        struct scatterlist *sg;
-        size_t buf_off = 0;
-        int i;
-
-        WARN_ON(!irqs_disabled());
-
-        for_each_sg(sgl, sg, nents, i) {
-                struct page *page;
-                int n = 0;
-                unsigned int sg_off = sg->offset;
-                unsigned int sg_copy = sg->length;
-
-                if (sg_copy > buflen)
-                        sg_copy = buflen;
-                buflen -= sg_copy;
-
-                while (sg_copy > 0) {
-                        unsigned int page_copy;
-                        void *p;
-
-                        page_copy = PAGE_SIZE - sg_off;
-                        if (page_copy > sg_copy)
-                                page_copy = sg_copy;
-
-                        page = nth_page(sg_page(sg), n);
-                        p = kmap_atomic(page, KM_BIO_SRC_IRQ);
-
-                        if (to_buffer)
-                                memcpy(buf + buf_off, p + sg_off, page_copy);
-                        else {
-                                memcpy(p + sg_off, buf + buf_off, page_copy);
-                                flush_kernel_dcache_page(page);
-                        }
-
-                        kunmap_atomic(p, KM_BIO_SRC_IRQ);
-
-                        buf_off += page_copy;
-                        sg_off += page_copy;
-                        if (sg_off == PAGE_SIZE) {
-                                sg_off = 0;
-                                n++;
-                        }
-                        sg_copy -= page_copy;
+        unsigned int offset = 0;
+        struct sg_mapping_iter miter;
+
+        sg_miter_start(&miter, sgl, nents, SG_MITER_ATOMIC);
+
+        while (sg_miter_next(&miter) && offset < buflen) {
+                unsigned int len;
+
+                len = min(miter.length, buflen - offset);
+
+                if (to_buffer)
+                        memcpy(buf + offset, miter.addr, len);
+                else {
+                        memcpy(miter.addr, buf + offset, len);
+                        flush_kernel_dcache_page(miter.page);
                 }
 
-                if (!buflen)
-                        break;
+                offset += len;
         }
 
-        return buf_off;
+        sg_miter_stop(&miter);
+
+        return offset;
 }
 
 /**
diff --git a/lib/smp_processor_id.c b/lib/smp_processor_id.c
index 3b4dc098181e..c4381d9516f6 100644
--- a/lib/smp_processor_id.c
+++ b/lib/smp_processor_id.c
@@ -11,7 +11,7 @@ notrace unsigned int debug_smp_processor_id(void)
 {
         unsigned long preempt_count = preempt_count();
         int this_cpu = raw_smp_processor_id();
-        cpumask_t this_mask;
+        cpumask_of_cpu_ptr_declare(this_mask);
 
         if (likely(preempt_count))
                 goto out;
@@ -23,9 +23,9 @@ notrace unsigned int debug_smp_processor_id(void)
          * Kernel threads bound to a single CPU can safely use
          * smp_processor_id():
          */
-        this_mask = cpumask_of_cpu(this_cpu);
+        cpumask_of_cpu_ptr_next(this_mask, this_cpu);
 
-        if (cpus_equal(current->cpus_allowed, this_mask))
+        if (cpus_equal(current->cpus_allowed, *this_mask))
                 goto out;
 
         /*