This patch indroduces mod_symname_hash, and its install/remove operations.
Since symbol_search() has to return the lowest address symbol and
symbol_search_next() returns the next lowest symbol, thus the installation
should be sorted ascendingly.

In mod_symname_hash_install_range scenario, spn are already arranged
ascendingly, so for mod_symname_hash_install:

Install spn previous to sp:

If sp is the start of bucket, and
1) spn->value is smaller than sp->value.

Install spn next to sp:

1) sp->name_hash_next is NULL or
2) sp->name_hash_next->value larger than spn->value

spn->value is the kernel address of the symbol and will not change.
So we use it mainly to determine the sequence. When spn->value equals
sp->value, they must be symbols within a kernel module.

Signed-off-by: Tao Liu <[email protected]>
---
 defs.h    |  1 +
 symbols.c | 73 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 74 insertions(+)

diff --git a/defs.h b/defs.h
index cbd45e5..bbdca79 100644
--- a/defs.h
+++ b/defs.h
@@ -2755,6 +2755,7 @@ struct symbol_table_data {
         double val_hash_searches;
         double val_hash_iterations;
         struct syment *symname_hash[SYMNAME_HASH];
+       struct syment *mod_symname_hash[SYMNAME_HASH];
        struct symbol_namespace kernel_namespace;
        struct syment *ext_module_symtable;
        struct syment *ext_module_symend;
diff --git a/symbols.c b/symbols.c
index 69dccdb..ad12d1c 100644
--- a/symbols.c
+++ b/symbols.c
@@ -1157,6 +1157,79 @@ symname_hash_install(struct syment *spn)
        }
 }
 
+/*
+ *  Install a single kernel module symbol into the mod_symname_hash.
+ */
+static void
+mod_symname_hash_install(struct syment *spn)
+{
+       struct syment *sp;
+       int index;
+
+       if (!spn)
+               return;
+
+       index = SYMNAME_HASH_INDEX(spn->name);
+
+       sp = st->mod_symname_hash[index];
+
+       if (!sp || (spn->value < sp->value)) {
+               st->mod_symname_hash[index] = spn;
+               spn->name_hash_next = sp;
+               return;
+       }
+       for (; sp; sp = sp->name_hash_next) {
+               if (!sp->name_hash_next ||
+                   spn->value < sp->name_hash_next->value) {
+                       spn->name_hash_next = sp->name_hash_next;
+                       sp->name_hash_next = spn;
+                       return;
+               }
+       }
+}
+
+static void
+mod_symname_hash_remove(struct syment *spn)
+{
+       struct syment *sp;
+       int index;
+
+       if (!spn)
+               return;
+
+       index = SYMNAME_HASH_INDEX(spn->name);
+
+       if (st->mod_symname_hash[index] == spn) {
+               st->mod_symname_hash[index] = spn->name_hash_next;
+               return;
+       }
+
+       for (sp = st->mod_symname_hash[index]; sp; sp = sp->name_hash_next) {
+               if (sp->name_hash_next == spn) {
+                       sp->name_hash_next = spn->name_hash_next;
+                       return;
+               }
+       }
+}
+
+static void
+mod_symtable_hash_install_range(struct syment *from, struct syment *to)
+{
+       struct syment *sp;
+
+       for (sp = from; sp <= to; sp++)
+               mod_symname_hash_install(sp);
+}
+
+static void
+mod_symtable_hash_remove_range(struct syment *from, struct syment *to)
+{
+       struct syment *sp;
+
+       for (sp = from; sp <= to; sp++)
+               mod_symname_hash_remove(sp);
+}
+
 /*
  *  Static kernel symbol value search
  */
-- 
2.29.2

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