Re: [Crash-utility] [PATCH v6 1/7] Implement install and remove operations for mod_symname_hash

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 <ltao(a)redhat.com&gt; --- 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