x86/ldt: Rename ldt_struct::size to ::nr_entries

... because this is exactly what it is: the number of entries in the
LDT. Calling it "size" is simply confusing and it is actually begging
to be called "nr_entries" or somesuch, especially if you see constructs
like:

	alloc_size = size * LDT_ENTRY_SIZE;

since LDT_ENTRY_SIZE is the size of a single entry.

There should be no functionality change resulting from this patch, as
the before/after output from tools/testing/selftests/x86/ldt_gdt.c
shows.

Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Andy Lutomirski <luto@amacapital.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170606173116.13977-1-bp@alien8.de
[ Renamed 'n_entries' to 'nr_entries' ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>

6 files changed, 31 insertions, 30 deletions

diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index 77a33096728d..d4d5e1ee8e9c 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -2333,7 +2333,7 @@ static unsigned long get_segment_base(unsigned int segment)
 
                 /* IRQs are off, so this synchronizes with smp_store_release */
                 ldt = lockless_dereference(current->active_mm->context.ldt);
-                if (!ldt || idx > ldt->size)
+                if (!ldt || idx > ldt->nr_entries)
                         return 0;
 
                 desc = &ldt->entries[idx];
diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h
index f20d7ea47095..5a93f6261302 100644
--- a/arch/x86/include/asm/mmu_context.h
+++ b/arch/x86/include/asm/mmu_context.h
@@ -47,7 +47,7 @@ struct ldt_struct {
          * allocations, but it's not worth trying to optimize.
          */
         struct desc_struct *entries;
-        unsigned int size;
+        unsigned int nr_entries;
 };
 
 /*
@@ -87,7 +87,7 @@ static inline void load_mm_ldt(struct mm_struct *mm)
          */
 
         if (unlikely(ldt))
-                set_ldt(ldt->entries, ldt->size);
+                set_ldt(ldt->entries, ldt->nr_entries);
         else
                 clear_LDT();
 #else
diff --git a/arch/x86/kernel/ldt.c b/arch/x86/kernel/ldt.c
index de503e7a64ad..a870910c8565 100644
--- a/arch/x86/kernel/ldt.c
+++ b/arch/x86/kernel/ldt.c
@@ -31,16 +31,16 @@ static void flush_ldt(void *__mm)
                 return;
 
         pc = &mm->context;
-        set_ldt(pc->ldt->entries, pc->ldt->size);
+        set_ldt(pc->ldt->entries, pc->ldt->nr_entries);
 }
 
 /* The caller must call finalize_ldt_struct on the result. LDT starts zeroed. */
-static struct ldt_struct *alloc_ldt_struct(unsigned int size)
+static struct ldt_struct *alloc_ldt_struct(unsigned int num_entries)
 {
         struct ldt_struct *new_ldt;
         unsigned int alloc_size;
 
-        if (size > LDT_ENTRIES)
+        if (num_entries > LDT_ENTRIES)
                 return NULL;
 
         new_ldt = kmalloc(sizeof(struct ldt_struct), GFP_KERNEL);
@@ -48,7 +48,7 @@ static struct ldt_struct *alloc_ldt_struct(unsigned int size)
                 return NULL;
 
         BUILD_BUG_ON(LDT_ENTRY_SIZE != sizeof(struct desc_struct));
-        alloc_size = size * LDT_ENTRY_SIZE;
+        alloc_size = num_entries * LDT_ENTRY_SIZE;
 
         /*
          * Xen is very picky: it requires a page-aligned LDT that has no
@@ -66,14 +66,14 @@ static struct ldt_struct *alloc_ldt_struct(unsigned int size)
                 return NULL;
         }
 
-        new_ldt->size = size;
+        new_ldt->nr_entries = num_entries;
         return new_ldt;
 }
 
 /* After calling this, the LDT is immutable. */
 static void finalize_ldt_struct(struct ldt_struct *ldt)
 {
-        paravirt_alloc_ldt(ldt->entries, ldt->size);
+        paravirt_alloc_ldt(ldt->entries, ldt->nr_entries);
 }
 
 /* context.lock is held */
@@ -92,8 +92,8 @@ static void free_ldt_struct(struct ldt_struct *ldt)
         if (likely(!ldt))
                 return;
 
-        paravirt_free_ldt(ldt->entries, ldt->size);
-        if (ldt->size * LDT_ENTRY_SIZE > PAGE_SIZE)
+        paravirt_free_ldt(ldt->entries, ldt->nr_entries);
+        if (ldt->nr_entries * LDT_ENTRY_SIZE > PAGE_SIZE)
                 vfree_atomic(ldt->entries);
         else
                 free_page((unsigned long)ldt->entries);
@@ -123,14 +123,14 @@ int init_new_context_ldt(struct task_struct *tsk, struct mm_struct *mm)
                 goto out_unlock;
         }
 
-        new_ldt = alloc_ldt_struct(old_mm->context.ldt->size);
+        new_ldt = alloc_ldt_struct(old_mm->context.ldt->nr_entries);
         if (!new_ldt) {
                 retval = -ENOMEM;
                 goto out_unlock;
         }
 
         memcpy(new_ldt->entries, old_mm->context.ldt->entries,
-               new_ldt->size * LDT_ENTRY_SIZE);
+               new_ldt->nr_entries * LDT_ENTRY_SIZE);
         finalize_ldt_struct(new_ldt);
 
         mm->context.ldt = new_ldt;
@@ -153,9 +153,9 @@ void destroy_context_ldt(struct mm_struct *mm)
 
 static int read_ldt(void __user *ptr, unsigned long bytecount)
 {
-        int retval;
-        unsigned long size;
         struct mm_struct *mm = current->mm;
+        unsigned long entries_size;
+        int retval;
 
         mutex_lock(&mm->context.lock);
 
@@ -167,18 +167,18 @@ static int read_ldt(void __user *ptr, unsigned long bytecount)
         if (bytecount > LDT_ENTRY_SIZE * LDT_ENTRIES)
                 bytecount = LDT_ENTRY_SIZE * LDT_ENTRIES;
 
-        size = mm->context.ldt->size * LDT_ENTRY_SIZE;
-        if (size > bytecount)
-                size = bytecount;
+        entries_size = mm->context.ldt->nr_entries * LDT_ENTRY_SIZE;
+        if (entries_size > bytecount)
+                entries_size = bytecount;
 
-        if (copy_to_user(ptr, mm->context.ldt->entries, size)) {
+        if (copy_to_user(ptr, mm->context.ldt->entries, entries_size)) {
                 retval = -EFAULT;
                 goto out_unlock;
         }
 
-        if (size != bytecount) {
+        if (entries_size != bytecount) {
                 /* Zero-fill the rest and pretend we read bytecount bytes. */
-                if (clear_user(ptr + size, bytecount - size)) {
+                if (clear_user(ptr + entries_size, bytecount - entries_size)) {
                         retval = -EFAULT;
                         goto out_unlock;
                 }
@@ -209,7 +209,7 @@ static int write_ldt(void __user *ptr, unsigned long bytecount, int oldmode)
 {
         struct mm_struct *mm = current->mm;
         struct ldt_struct *new_ldt, *old_ldt;
-        unsigned int oldsize, newsize;
+        unsigned int old_nr_entries, new_nr_entries;
         struct user_desc ldt_info;
         struct desc_struct ldt;
         int error;
@@ -248,17 +248,18 @@ static int write_ldt(void __user *ptr, unsigned long bytecount, int oldmode)
 
         mutex_lock(&mm->context.lock);
 
-        old_ldt = mm->context.ldt;
-        oldsize = old_ldt ? old_ldt->size : 0;
-        newsize = max(ldt_info.entry_number + 1, oldsize);
+        old_ldt       = mm->context.ldt;
+        old_nr_entries = old_ldt ? old_ldt->nr_entries : 0;
+        new_nr_entries = max(ldt_info.entry_number + 1, old_nr_entries);
 
         error = -ENOMEM;
-        new_ldt = alloc_ldt_struct(newsize);
+        new_ldt = alloc_ldt_struct(new_nr_entries);
         if (!new_ldt)
                 goto out_unlock;
 
         if (old_ldt)
-                memcpy(new_ldt->entries, old_ldt->entries, oldsize * LDT_ENTRY_SIZE);
+                memcpy(new_ldt->entries, old_ldt->entries, old_nr_entries * LDT_ENTRY_SIZE);
+
         new_ldt->entries[ldt_info.entry_number] = ldt;
         finalize_ldt_struct(new_ldt);
 
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index b6840bf3940b..9c39ab8bcc41 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -142,7 +142,7 @@ void release_thread(struct task_struct *dead_task)
                         pr_warn("WARNING: dead process %s still has LDT? <%p/%d>\n",
                                 dead_task->comm,
                                 dead_task->mm->context.ldt->entries,
-                                dead_task->mm->context.ldt->size);
+                                dead_task->mm->context.ldt->nr_entries);
                         BUG();
                 }
 #endif
diff --git a/arch/x86/kernel/step.c b/arch/x86/kernel/step.c
index f07f83b3611b..5f25cfbd952e 100644
--- a/arch/x86/kernel/step.c
+++ b/arch/x86/kernel/step.c
@@ -34,7 +34,7 @@ unsigned long convert_ip_to_linear(struct task_struct *child, struct pt_regs *re
 
                 mutex_lock(&child->mm->context.lock);
                 if (unlikely(!child->mm->context.ldt ||
-                             seg >= child->mm->context.ldt->size))
+                             seg >= child->mm->context.ldt->nr_entries))
                         addr = -1L; /* bogus selector, access would fault */
                 else {
                         desc = &child->mm->context.ldt->entries[seg];
diff --git a/arch/x86/math-emu/fpu_system.h b/arch/x86/math-emu/fpu_system.h
index 5e044d506b7a..a179254a5122 100644
--- a/arch/x86/math-emu/fpu_system.h
+++ b/arch/x86/math-emu/fpu_system.h
@@ -27,7 +27,7 @@ static inline struct desc_struct FPU_get_ldt_descriptor(unsigned seg)
 #ifdef CONFIG_MODIFY_LDT_SYSCALL
         seg >>= 3;
         mutex_lock(&current->mm->context.lock);
-        if (current->mm->context.ldt && seg < current->mm->context.ldt->size)
+        if (current->mm->context.ldt && seg < current->mm->context.ldt->nr_entries)
                 ret = current->mm->context.ldt->entries[seg];
         mutex_unlock(&current->mm->context.lock);
 #endif